PURPOSE: To impart uniform gloss to metallic surfaces and to improve the cold workability, such as drawability, of these surfaces by subjecting the metallic surfaces to a zinc phosphate-calcium treatment by using a son. specified in the content ratios of respective ions of Ca, Zn and PO4.

CONSTITUTION: The aq. soln. which contains 10 to 40g/l Ca2+ ions, 10 to 40g/l Zn2+ ions, 10 to 100g/l PO43- ions, 10 to 100g/l NO3- ions as an accelerator or 0.1 to 2.0g/l org. nitro compd. and has a pH value of 2.0 to 3.8 is prepd. The ratio of the free acid to the total acid in the soln. is specified to 1:4 to 1:100. After the metallic surfaces of wire blanks, etc., are subjected to washing and etching, the metallic surface are brought into contact with the aq. soln. described above. If the metallic blanks after such phosphate treatment are subjected to drawing, the wires, etc., having the uniform gloss are obtd. The formed bath sludge is little and the life of drawing dies, etc., is prolonged.