To provide a method for manufacturing a supporting body for a planographic printing plate having an excellent printing durability.

In the method for manufacturing supporting body for a planographic printing plate to be manufactured through at least a surface roughening treatment process and an anodizing treatment process, the surface roughening treatment process has at least the electrolytic surface roughening treatment process and the alkali etching treatment process, the anode total electric quantity in the electrolytic surface roughening treatment is made to be 50-800 C/dm2, the ratio between the anode total electric amount and the cathode total electric amount is made to be 0.7-1.0, the average velocity of electrolytic solution is made to be 500-4000 mm/sec and the width direction velocity distribution is made to be within ±50% of the average velocity. In the anodizing treatment for the anodizing treatment process, electrolytic solution containing sulfuric acid is used with the temperature, the conductive rate, and the specific gravity, of the electrolytic solution being controlled to keep constant, the width direction velocity distribution is made to be within ±50% of the average velocity with the average velocity of the electrolytic solution being made to 10-2500 mm/sec, and the current density is made to be 2-50 A/dm2.