A projection device includes a semiconductor light-emitting element, a rotary wheel configured to emit lights of a plurality of colors in a time-division manner by using light which the semiconductor light-emitting element emits, and a controller configured to start, at a time of activating the device, rotation of the rotary wheel and output of a signal, which instructs a turn-on timing, to the semiconductor light-emitting element, in a state in which supply of power to the semiconductor light-emitting element is stopped, and to start, thereafter, the supply of the power to the semiconductor light-emitting element, based on a predetermined condition relating to an activation state.