Signal cancelling device for rocking vehicle

A turn signal cancelling device 100 for a motorcycle 10 includes determining means 126 for determining whether the motorcycle 10 is travelling straight ahead or is turning and turn signal cancellation control means 128. When a vehicle speed is equal to or lower than a predetermined speed and a driving force is equal to or larger than a predetermined driving force when the motorcycle 10 is turning, the turn signal cancellation control means 128 enters a standby state. If it is determined that the motorcycle 10 is travelling straight ahead during the standby state, the turn signal cancellation control means 128 automatically deactivates a turn signal 102. If the driving force becomes smaller than the predetermined driving force or the turn signal 102 becomes inactive during the standby state, the turn signal cancellation control means 128 cancels the standby state. This provides improved accuracy of turn signal cancellation.