diff --git a/lib/matrix.rb b/lib/matrix.rb
index 76bec92..390aaf6 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -60,6 +60,7 @@ end
 # * #minor(*param)
 # * #first_minor(row, column)
 # * #cofactor(row, column)
+# * #column_merge(*matrices)
 #
 # Properties of a matrix:
 # * #diagonal?
@@ -636,6 +637,21 @@ class Matrix
     det_of_minor * (-1) ** (row + column)
   end

+  #
+  # Merge matrices between columns.
+  #
+  #   Matrix[[1, 2], [3, 4]].column_merge(Matrix[[5, 6]])
+  #     => 1 2
+  #        3 4
+  #        5 6
+  #
+  def column_merge(*matrices)
+    if matrices.any?{|m| m.column_size != column_size }
+      raise ErrDimensionMismatch, "all matrices should have same column size"
+    end
+    new_matrix [self, *matrices].map(&:to_a).flatten(1)
+  end
+
   #--
   # TESTING -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
   #++