PURPOSE: To provide a corrosion-resistant paint which can be thick-coated and has excellent resistance to water and impact, etc., by incorporating a polyurethane resin obtd. by reacting a polyisocyanate compd., a specified polyol mixture and an arom. hydrocarbon oil (resin).

CONSTITUTION: A polyisocyanate compd. (A) (e.g. tolylene diisocyanate or diphenylmethane diisocyanate), a polyol (B) composed of castor oil polyol and a polyol (e.g. diethylene glycol) other than castor oil wherein the sum of their hydroxyl values is 180mgKOH/g or above, and an arom. hydrocarbon oil (e.g. alkylnaphthalene) or an arom. hydrocarbon resin (e.g. cumarone/indene resin) (C) are reacted together to prepare a polyester resin. The polyester resin is used as a main component to obtain the desired corrosion-resistant paint.