PROBLEM TO BE SOLVED: To provide a power supply system of agricultural machines dispensing with mounting/demounting of a harness for power supply when mounting/demounting a working machine, which is mounted on a tractor for performing agricultural work, with respect to the tractor.SOLUTION: This power supply system of agricultural machines includes: the working machine 2 that is mounted on the tractor 1 for performing the agricultural work and is mountable/demountable with respect to the tractor 1； a power transmission system 15 that is installed in the side of the tractor 1 and connected to a power supply 11 provided in the tractor 1； a transmission device 16 that is installed in the side of the tractor 1 and connected to the power transmission system 15； a receiving device 23 that is installed in the working machine 2； a power receiving system 22 that is installed in the working machine 2 and connected to the receiving device 23； and an output device 80 that is installed in the working machine 2 and operates by the power transmitted from the power receiving system 22. The power is wirelessly transmitted between the transmission device 16 and the receiving device 23, and the power transmission system 15 and the power receiving system 22 convert the power for the wireless power transmission.
