diff --git a/lib/typeprof/core/ast/sig_type.rb b/lib/typeprof/core/ast/sig_type.rb
index aa0c896f..ee61ca02 100644
--- a/lib/typeprof/core/ast/sig_type.rb
+++ b/lib/typeprof/core/ast/sig_type.rb
@@ -108,13 +108,19 @@ def initialize(raw_decl, raw_type_params, raw_block, lenv)
           param = raw_decl.type.rest_positionals
           @rest_positionals = param ? AST.create_rbs_type(param.type, lenv) : nil
 
-          @req_keywords = raw_decl.type.required_keywords.to_h do |key, ty|
+          @req_keyword_keys = []
+          @req_keyword_values = []
+          raw_decl.type.required_keywords.each do |key, ty|
             raise "unsupported argument type: #{ ty.class }" if !ty.is_a?(RBS::Types::Function::Param)
-            [key, AST.create_rbs_type(ty.type, lenv)]
+            @req_keyword_keys << key
+            @req_keyword_values << AST.create_rbs_type(ty.type, lenv)
           end
-          @opt_keywords = raw_decl.type.optional_keywords.to_h do |key, ty|
+          @opt_keyword_keys = []
+          @opt_keyword_values = []
+          raw_decl.type.optional_keywords.each do |key, ty|
             raise "unsupported argument type: #{ ty.class }" if !ty.is_a?(RBS::Types::Function::Param)
-            [key, AST.create_rbs_type(ty.type, lenv)]
+            @opt_keyword_keys << key
+            @opt_keyword_values << AST.create_rbs_type(ty.type, lenv)
           end
           param = raw_decl.type.rest_keywords
           @rest_keywords = param ? AST.create_rbs_type(param.type, lenv) : nil
@@ -124,8 +130,10 @@ def initialize(raw_decl, raw_type_params, raw_block, lenv)
           @post_positionals = []
           @opt_positionals = []
           @rest_positionals = SigTyBaseAnyNode.new(raw_decl, lenv)
-          @req_keywords = {}
-          @opt_keywords = {}
+          @req_keyword_keys = []
+          @req_keyword_values = []
+          @opt_keyword_keys = []
+          @opt_keyword_values = []
           @rest_keywords = nil
         end
 
@@ -137,8 +145,10 @@ def initialize(raw_decl, raw_type_params, raw_block, lenv)
       attr_reader :post_positionals
       attr_reader :opt_positionals
       attr_reader :rest_positionals
-      attr_reader :req_keywords
-      attr_reader :opt_keywords
+      attr_reader :req_keyword_keys
+      attr_reader :req_keyword_values
+      attr_reader :opt_keyword_keys
+      attr_reader :opt_keyword_values
       attr_reader :rest_keywords
       attr_reader :return_type
 
@@ -148,12 +158,17 @@ def subnodes = {
         post_positionals:,
         opt_positionals:,
         rest_positionals:,
-        req_keywords:,
-        opt_keywords:,
+        req_keyword_values:,
+        opt_keyword_values:,
         rest_keywords:,
         return_type:,
       }
-      def attrs = { type_params:, block_required: }
+      def attrs = {
+        type_params:,
+        req_keyword_keys:,
+        opt_keyword_keys:,
+        block_required:,
+      }
     end
 
     class SigTyNode < Node
diff --git a/lib/typeprof/core/graph/box.rb b/lib/typeprof/core/graph/box.rb
index 9c62aeb6..c13bb119 100644
--- a/lib/typeprof/core/graph/box.rb
+++ b/lib/typeprof/core/graph/box.rb
@@ -279,10 +279,10 @@ def show
           args << arg.show
         end
 
-        method_type.req_keywords.each do |key, arg|
+        method_type.req_keyword_keys.zip(method_type.req_keyword_values) do |key, arg|
           args << "#{ key }: #{arg.show}"
         end
-        method_type.opt_keywords.each do |key, arg|
+        method_type.opt_keyword_keys.zip(method_type.opt_keyword_values) do |key, arg|
           args << "?#{ key }: #{arg.show}"
         end
         if method_type.rest_keywords
diff --git a/scenario/regressions/rbs-inline-keywords.rb b/scenario/regressions/rbs-inline-keywords.rb
new file mode 100644
index 00000000..6ce15cfd
--- /dev/null
+++ b/scenario/regressions/rbs-inline-keywords.rb
@@ -0,0 +1,12 @@
+## update
+#: (b: untyped) -> nil
+def a(b:); end
+
+## update
+#: (b: untyped) -> nil
+def a(b:); end
+
+## assert
+class Object
+  def a: (b: untyped) -> nil
+end