PURPOSE: To remove foreign matter from painting equipment and to easily and certainly wash the painting equipment by arranging an accumulating member on the inner bottom surface of a paint tank to discharge the detergent in the paint tank from the cylindrical part of the accumulating member while settling the foreign matter in the detergent on the accumulating member.

CONSTITUTION: Painting equipment is provided so as to coat a car body with paint and equipped with a paint tank 10 and the paint supply passage 20 connected thereto. The paint tank 10 has the paint supply port 12 to which the paint supply passage 20 is connected opened to the central part of the bottom surface 11 molded into a funnel shape thereof. In this case, a washing jig is prepared in the painting equipment. That is, the washing jig is constituted by forming a cylindrical part 40a to the inside central part of an accumulating member 40 molded into the same shape as the bottom surface of the paint tank 10 and providing the center hole (discharge passage) 40C having the same inner diameter as the paint supply port 12 in the cylindrical part 40a. The detergent T stirred by a stirrer 30 is discharged from the center hole 40C and the foreign matter in the detergent T is settled on the accumulating member 40.