To reduce the size and weight of a power supply equipment and moreover increase the discharge capacity and output by installing 2 kinds of storage batteries to electric motor cars and supplying power by selecting one of the batteries depending on the value of a discharge current requested.

A power supply equipment 1 for electric motor car has two kinds of storage batteries: a battery A with a large energy density, and a battery B with a large output density, and power can be supplied by selecting one of the batteries depending on the value of the discharge current requested. That is, if the detected information from discharge current detection means 10 exceeds a predetermined value, then a change-over switch SWa opens and a change-over switch Swb closes, power is supplied from the battery B to a load 4 and, if it is lower than the predetermined value, then the change-over switch SWb is opened, charge-over switch SWa is closed, and power is supplied from the battery A to the load 4. The switching of the batteries A and B is indicated on a power supply switching means 23. As started above, the compact, lightweight power source having large discharge power and output can be obtained for the electric motor car.