To provide a drive unit capable of preventing air pollution by a diesel engine used as propulsive power.

For reduction in exhaust gas particles from a diesel engine, a rechargeable battery is converted into three-phase AC with a VVVF inverter and is then connected to a highly efficient and inexpensive SR motor with high performance to obtain traveling power, thus reducing air pollution. In charging the rechargeable battery as a power source, charging equipment for economical use at night, which is installed inside a harbor, is used for safety and convenience of users.