To improve alarm precision when a strong wind blows on a racing truck.

This false start warning device of a wind velocity and wind direction sensing type is provided with a wind velocity and wind direction sensor 101 installed on the ground (or on water) near a start line, a wind information laser emitting part 102 emitting wind information obtained from the sensor 101 from on the ground (or on water) toward a boat, a light receiving part 61c receiving an optical signal from the part 102 and a boat mounting warning part 60 provided with a light receiving part 61a receiving an optical signal from resetting laser emitting parts 4a and 4b, a clock 62 starting count down based on the output signal of the part 61a and outputting a time signal, a calculating and judging part 63 calculating the velocity of the boat based on the time signal and the output signals of 61b and 61c and judging the existence of the possibility of making a false start and a display part 64 displaying the judging result.