To provide an underwater power supply system capable of supplying electric power to one or more underwater movement bodies moving comparatively deep in water without surfacing the underwater movement bodies near to a water surface.

An underwater power supply system includes an up-down station 20 which moves up and down in water between a depth at which an underwater movement body 10 works and around a water surface 2, and a charging station 30 which supplies electric power to the up-down station 20 in a non-contact manner around the water surface 2. In the above depth, the underwater movement body 10 moves close to the up-down station 20, which supplies the electric power to the underwater movement body 10 in a non-contact manner.