To secure an operation starting voltage necessary for a start-up of an engine without turning-off of a power switch once when the start-up of the engine is tried again after the start-up of the engine ended in a failure.

An engine controller 1 has a power source for an engine, a control means connected to the power source through a power switch SW1, and a load 12 connected to between the control means and the power switch SW1 through a switching means. When a signal of an engine speed not less than a prescribed speed is input into the control means, the control means closes the switching means so that the load 12 is connected to the power source. Otherwise, when the signal of the engine speed not less than the prescribed speed is not input into the control means, the control means opens the switching means so that the load 12 is disconnected from the power source.