To improve durability of a main relay by suppressing the number of times of connection of the main relay when charging a sub-battery after control for suppressing engine racing in an engine controller.

When prescribed restart conditions are established (S2; Yes), after startup control by combustion starting is executed (S3), it is determined whether complete explosion is determined or not. When complete explosion is determined (S4; Yes), control for suppressing racing is executed. Namely, ignition timing is retarded (S5), a throttle is totally closed (S6), and a power-generation regulating voltage by an alternator 4 is set to 11.5V for a prescribed period of time (for example, 5-10 cycles) (S7).