The coating film peeling nut of the present invention has a notch 13 formed in an inner surface of a nut main body 10 on which a female screw 12 is formed, the notch 13 extending in a direction different from that of a lead angle of the female screw 12. The notch 13 is formed helically, and a winding direction thereof is the same as that of the female screw 12. A pitch of the notch 13 is 2 to 10 times a pitch of the female screw 12, and a depth of the notch 13 is 20 to 80% of a thread height of the female screw 12.