To further increase the effective pulse rate of a light source device.

A light source device is provided with a plurality of light sources 1a-1h which emit radiant light beams, one or more reflecting surfaces 2a, and a rotary reflecting body 2 which emits the radiant light beams emitted from the light sources 1a-1h along the common optical path L of the light sources 1a-1h. The light source device is also provided with a position detector 5 which detects the position of the reflecting surfaces 2a of the reflecting body 2, a timing control circuit 6 which outputs synchronizing signals for driving the light sources 1a-1h synchronously to the position of the reflecting body 2, and a power source circuit 7 which successively drives the light sources 1a-1h with pulses based on the output signal of the control circuit 6.