PROBLEM TO BE SOLVED: To output a proper vehicle speed to a work device.SOLUTION: In a vehicle speed detector 13 including a reception part 20 which receives satellite signals from a positioning satellite 15 and is attached to a vehicle body having a work device, and a vehicle speed calculation part 21 which calculates a vehicle speed of the vehicle body on the basis of the satellite signals received by the reception part 20, the vehicle speed calculation part 21 includes a first vehicle speed calculation part 25 which calculates a first vehicle speed that is a vehicle speed of the vehicle body on the basis of a carrier wave phase of the satellite signals, and a second vehicle speed calculation part 26 which calculates a second vehicle speed that is a vehicle speed of the vehicle body on the basis of Doppler shift when the reception part 20 receives the satellite signals.
