A cancelling device for a turn signal includes a cam guide member rotated by a steering wheel, a cylindrical cam body fitted on the outer periphery of the cam guide member in such a manner as to be pivotal, and a driving mechanism for bringing the cam guide member into engagement with the cylindrical cam body after eliminating a predetermined amount of play when the steering wheel is turned so as to allow the cylindrical cam body to be turned. The cylindrical cam body has first and second cam portions formed thereon. The cam guide member has a first slip portion for allowing the first cam portion to be elastically deformed inwardly when the cylindrical cam body is turned to the right and the first cam portion thereby makes contact with a ratchet portion of a mechanism portion located at a cancelling position. The cam guide member also has a second slip portion for allowing the second cam portion to be elastically deformed inward when the cylindrical cam body is turned to the left and the second cam portion thereby makes contact with the ratchet portion located at the cancelling position. In consequence, a reverse cancelling angle can be set at a value larger than that of a cancel preparation angle.