Provided is a power supply system including a crane and a power supply truck. In the power supply system, a linkage mechanism efficiently transmits a force in a travel direction x to the power supply truck, while not transmitting any force in a transverse direction y or a twisting direction, and has a highly durable configuration. In a power supply system 1 for a crane in which a crane 2 for loading and unloading a container for marine transportation is linked to a power supply truck 3 for supplying power while following the crane 2, with a linkage mechanism 4, the linkage mechanism 4 includes a receiving member 10 disposed on the power supply truck 3, and a pushing member 11 disposed on the crane 2. The power supply system 1 includes the linkage mechanism 4 configured in a manner that, when the crane 2 moves in a travel direction x, the pushing member 11 comes into contact with the receiving member 10, to transmit a force of the crane 2 moving in the travel direction x to the power supply truck 3, and when the crane 2 moves in a transverse direction y intersecting the travel direction x, the receiving member 10 does not disturb move of the pushing member 11 and a force of the crane 2 moving in the transverse direction y is not transmitted to the power supply truck 3.