To provide a sleeve flange type fitting device which can wash a groove to house a balance weight easily, and can fix the balance weight without using a steel ball.

A sleeve flange type fitting device 1 to fit a grinding wheel to the spindle of a grinder is composed of a sleeve flange 10 forming a sleeve part 12 and a flange part 11; a push plate 20 fitted to the sleeve part 12 in order to fix a grinding wheel to the flange part 11; a cover fitted to the push plate 20; a balance weight 30 which consists of three balance weights received to the circular recess formed to the push plate 20, and has the first circular arc form side surface 302 and the second circular arc form side surface 304 containing with the side surface at the outer side near the outer peripheral edge of the push plate 20; and a nut 50 screwed to the end of the sleeve part 12, and operates a pressing force to the cover 40.