Disclosed is a vehicle turn signal switch device whereby the production of knocking sounds by a cancellation pin (42) when a steering wheel (11) is turned in the direction of a turn signal is suppressed. A turn signal switch device (16) comprises a fixed member (21) and a movable plate (22). The cancellation pin (42), which is supported by the fixed member (21) and the movable plate (22) in such a manner that the cancellation pin can swing and move forward and backward relative to a cancellation cam (41), comprises a sliding-contact surface (51) that is in sliding contact with the fixed member (21). The cancellation pin (42) is biased by a return spring (45) in the direction (A1) of the cancellation cam (41) and in the direction (A2) of the sliding contact of the sliding-contact surface (51) with the fixed member (21).