A metal surface treatment method for improving uniformity of a cathodic electrodeposition coating film, wherein the method comprises: a surface treatment step for a metal base material to treat the surface of a metal base material and to form a rust-resistant film using a metal surface treatment composition comprising zirconium and/or titanium ions and at least one adhesive imparting agent selected from the group consisting of silicon-containing compound, adhesive imparting metal ion and adhesive imparting resin; a post-treatment step selected from the group consisting of any combination of processes (a) and (d) or of any combination of processes (a) and (e), wherein (a) is a process for contact treatment of all or a part of the metal base material in an alkali solution having a pH of at least 9, after the surface treatment step; (d) is a process for contact treatment of all or a part of the metal base material in an oxidizing agent, after the surface treatment step; (e) is a process for contact treatment of all or a part of the metal base material in an oxidizing agent and thereafter washing treatment with water, after the surface treatment step; wherein the oxidizing agent is one selected from the group consisting of nitric acid, nitrous acid, sulfuric acid, sulfurous acid, persulfate, phosphoric acid, hydrochloric acid, bromic acid, an iodine compound, chloric acid, hydrogen peroxide, HMnO 4, HVO 3, H 2 WO 4 H 2 M O O 4, and respective salt of each thereof; and an electrodeposition coating step by electropainting the metal material with a cathodic electrodeposition coating material. a surface treatment step for a metal base material to treat the surface of a metal base material and to form a rust-resistant film using a metal surface treatment composition comprising zirconium and/or titanium ions and at least one adhesive imparting agent selected from the group consisting of silicon-containing compound, adhesive imparting metal ion and adhesive imparting resin; a post-treatment step selected from the group consisting of any combination of processes (a) and (d) or of any combination of processes (a) and (e), wherein (a) is a process for contact treatment of all or a part of the metal base material in an alkali solution having a pH of at least 9, after the surface treatment step; (d) is a process for contact treatment of all or a part of the metal base material in an oxidizing agent, after the surface treatment step; (e) is a process for contact treatment of all or a part of the metal base material in an oxidizing agent and thereafter washing treatment with water, after the surface treatment step; wherein (a) is a process for contact treatment of all or a part of the metal base material in an alkali solution having a pH of at least 9, after the surface treatment step; (d) is a process for contact treatment of all or a part of the metal base material in an oxidizing agent, after the surface treatment step; (e) is a process for contact treatment of all or a part of the metal base material in an oxidizing agent and thereafter washing treatment with water, after the surface treatment step; wherein the oxidizing agent is one selected from the group consisting of nitric acid, nitrous acid, sulfuric acid, sulfurous acid, persulfate, phosphoric acid, hydrochloric acid, bromic acid, an iodine compound, chloric acid, hydrogen peroxide, HMnO 4, HVO 3, H 2 WO 4 H 2 M O O 4, and respective salt of each thereof; and an electrodeposition coating step by electropainting the metal material with a cathodic electrodeposition coating material.