Provided is a light source apparatus capable of outputting light with a high light level stably and efficiently. The light source apparatus is provided with a plurality of light source device that are disposed on a ring and that emit illumination light toward the central axis of the ring by being lit in a sequential pulsed fashion a light-guide portion having a light entrance surface that is rotatably disposed on the central axis and on which the illumination light emitted from the light source devices is incident, and a reflecting surface that reflects the incident illumination light in the direction along the central axis and a driving device that controls a pulsed-lighting phase range, which is a period during which the light source devices are lit according to the rotation phase of the light-guide portion wherein the driving device controls the pulsed-lighting phase range (W) such that, when the pulsed-lighting phase range (W) is shorter than a maximum-pulse phase range (M), which is the longest period during which the illumination light emitted from the light source devices is incident on the light entrance surface, a preceding light-out phase range (F) and a succeeding light-out phase range (R), which are periods during which the light source devices are turned off, are provided before and after the pulsed-lighting phase range (W) in the maximum-pulse phase range (M).
