diff --git a/enc/make_encmake.rb b/enc/make_encmake.rb
index fcfc2c9267..a0bf4be969 100755
--- a/enc/make_encmake.rb
+++ b/enc/make_encmake.rb
@@ -121,11 +121,7 @@ ENCS, ENC_DEPS = target_encodings
 ATRANS, TRANS = target_transcoders
 
 if File.exist?(depend = File.join($srcdir, "depend"))
-  if ERB.instance_method(:initialize).parameters.assoc(:key) # Ruby 2.6+
-    erb = ERB.new(File.read(depend), trim_mode: '%')
-  else
-    erb = ERB.new(File.read(depend), nil, '%')
-  end
+  erb = ERB.new(File.read(depend), trim_mode: '%')
   erb.filename = depend
   tmp = erb.result(binding)
   dep = "\n#### depend ####\n\n" << depend_rules(tmp).join
@@ -139,11 +135,7 @@ File.open(ARGV[0], 'wb') {|f|
 }
 if MODULE_TYPE == :static
   filename = "encinit.c.erb"
-  if ERB.instance_method(:initialize).parameters.assoc(:key) # Ruby 2.6+
-    erb = ERB.new(File.read(File.join($srcdir, filename)), trim_mode: '%-')
-  else
-    erb = ERB.new(File.read(File.join($srcdir, filename)), nil, '%-')
-  end
+  erb = ERB.new(File.read(File.join($srcdir, filename)), trim_mode: '%-')
   erb.filename = "enc/#{filename}"
   tmp = erb.result(binding)
   begin
diff --git a/ext/socket/mkconstants.rb b/ext/socket/mkconstants.rb
index 04719fff28..4271e40cd8 100644
--- a/ext/socket/mkconstants.rb
+++ b/ext/socket/mkconstants.rb
@@ -76,15 +76,11 @@ def each_name(pat)
   }
 end
 
-erb_new = lambda do |src, safe, trim|
-  if ERB.instance_method(:initialize).parameters.assoc(:key) # Ruby 2.6+
-    ERB.new(src, trim_mode: trim)
-  else
-    ERB.new(src, safe, trim)
-  end
+erb_new = lambda do |src, trim|
+  ERB.new(src, trim_mode: trim)
 end
 
-erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_const_decls")
+erb_new.call(<<'EOS', '%').def_method(Object, "gen_const_decls")
 % each_const {|guard, name, default_value|
 #if !defined(<%=name%>)
 # if defined(HAVE_CONST_<%=name.upcase%>)
@@ -98,7 +94,7 @@ erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_const_decls")
 % }
 EOS
 
-erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_const_defs_in_guard(name, default_value)")
+erb_new.call(<<'EOS', '%').def_method(Object, "gen_const_defs_in_guard(name, default_value)")
 #if defined(<%=name%>)
     /* <%= COMMENTS[name] %> */
     rb_define_const(rb_cSocket, <%=c_str name%>, INTEGER2NUM(<%=name%>));
@@ -107,7 +103,7 @@ erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_const_defs_in_guard(name
 #endif
 EOS
 
-erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_const_defs")
+erb_new.call(<<'EOS', '%').def_method(Object, "gen_const_defs")
 % each_const {|guard, name, default_value|
 %   if guard
 #if <%=guard%>
@@ -157,7 +153,7 @@ def each_names_with_len(pat, prefix_optional=nil)
   }
 end
 
-erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_name_to_int_decl(funcname, pat, prefix_optional, guard=nil)")
+erb_new.call(<<'EOS', '%').def_method(Object, "gen_name_to_int_decl(funcname, pat, prefix_optional, guard=nil)")
 %if guard
 #ifdef <%=guard%>
 int <%=funcname%>(const char *str, long len, int *valp);
@@ -167,7 +163,7 @@ int <%=funcname%>(const char *str, long len, int *valp);
 %end
 EOS
 
-erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_name_to_int_func_in_guard(funcname, pat, prefix_optional, guard=nil)")
+erb_new.call(<<'EOS', '%').def_method(Object, "gen_name_to_int_func_in_guard(funcname, pat, prefix_optional, guard=nil)")
 int
 <%=funcname%>(const char *str, long len, int *valp)
 {
@@ -189,7 +185,7 @@ int
 }
 EOS
 
-erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_name_to_int_func(funcname, pat, prefix_optional, guard=nil)")
+erb_new.call(<<'EOS', '%').def_method(Object, "gen_name_to_int_func(funcname, pat, prefix_optional, guard=nil)")
 %if guard
 #ifdef <%=guard%>
 <%=gen_name_to_int_func_in_guard(funcname, pat, prefix_optional, guard)%>
@@ -218,7 +214,7 @@ def reverse_each_name_with_prefix_optional(pat, prefix_pat)
   end
 end
 
-erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_int_to_name_hash(hash_var, pat, prefix_pat)")
+erb_new.call(<<'EOS', '%').def_method(Object, "gen_int_to_name_hash(hash_var, pat, prefix_pat)")
     <%=hash_var%> = st_init_numtable();
 % reverse_each_name_with_prefix_optional(pat, prefix_pat) {|n,s|
 #ifdef <%=n%>
@@ -227,7 +223,7 @@ erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_int_to_name_hash(hash_va
 % }
 EOS
 
-erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_int_to_name_func(func_name, hash_var)")
+erb_new.call(<<'EOS', '%').def_method(Object, "gen_int_to_name_func(func_name, hash_var)")
 ID
 <%=func_name%>(int val)
 {
@@ -238,7 +234,7 @@ ID
 }
 EOS
 
-erb_new.call(<<'EOS', nil, '%').def_method(Object, "gen_int_to_name_decl(func_name, hash_var)")
+erb_new.call(<<'EOS', '%').def_method(Object, "gen_int_to_name_decl(func_name, hash_var)")
 ID <%=func_name%>(int val);
 EOS
 
@@ -287,7 +283,7 @@ def_intern('rsock_intern_udp_optname',  /\AUDP_/, "UDP_")
 def_intern('rsock_intern_scm_optname',  /\ASCM_/, "SCM_")
 def_intern('rsock_intern_local_optname',  /\ALOCAL_/, "LOCAL_")
 
-result = erb_new.call(<<'EOS', nil, '%').result(binding)
+result = erb_new.call(<<'EOS', '%').result(binding)
 /* autogenerated file */
 
 <%= INTERN_DEFS.map {|vardef, gen_hash, decl, func| vardef }.join("\n") %>
@@ -330,7 +326,7 @@ init_constants(void)
 
 EOS
 
-header_result = erb_new.call(<<'EOS', nil, '%').result(binding)
+header_result = erb_new.call(<<'EOS', '%').result(binding)
 /* autogenerated file */
 <%= gen_const_decls %>
 <%= NAME_TO_INT_DEFS.map {|decl, func| decl }.join("\n") %>
diff --git a/tool/generic_erb.rb b/tool/generic_erb.rb
index 6607d5c256..9326309ff6 100644
--- a/tool/generic_erb.rb
+++ b/tool/generic_erb.rb
@@ -27,11 +27,7 @@ vpath = out.vpath
 output, vpath = output, vpath
 
 result = templates.map do |template|
-  if ERB.instance_method(:initialize).parameters.assoc(:key) # Ruby 2.6+
-    erb = ERB.new(File.read(template), trim_mode: '%-')
-  else
-    erb = ERB.new(File.read(template), nil, '%-')
-  end
+  erb = ERB.new(File.read(template), trim_mode: '%-')
   erb.filename = template
   source ? erb.src : proc{erb.result(binding)}.call
 end
diff --git a/tool/ruby_vm/helpers/dumper.rb b/tool/ruby_vm/helpers/dumper.rb
index c083dffa7a..8a04041da9 100644
--- a/tool/ruby_vm/helpers/dumper.rb
+++ b/tool/ruby_vm/helpers/dumper.rb
@@ -33,11 +33,7 @@ class RubyVM::Dumper
   rescue Errno::ENOENT
     raise "don't know how to generate #{path}"
   else
-    if ERB.instance_method(:initialize).parameters.assoc(:key) # Ruby 2.6+
-      erb = ERB.new(src, trim_mode: '%-')
-    else
-      erb = ERB.new(src, nil, '%-')
-    end
+    erb = ERB.new(src, trim_mode: '%-')
     erb.filename = path.to_path
     return erb
   end
diff --git a/tool/transcode-tblgen.rb b/tool/transcode-tblgen.rb
index b19f68bac4..1257a92d38 100644
--- a/tool/transcode-tblgen.rb
+++ b/tool/transcode-tblgen.rb
@@ -1078,11 +1078,7 @@ if __FILE__ == $0
   end
 
   libs1 = $".dup
-  if ERB.instance_method(:initialize).parameters.assoc(:key) # Ruby 2.6+
-    erb = ERB.new(src, trim_mode: '%')
-  else
-    erb = ERB.new(src, nil, '%')
-  end
+  erb = ERB.new(src, trim_mode: '%')
   erb.filename = arg
   erb_result = erb.result(binding)
   libs2 = $".dup