To provide a light source device suitably used for a high-luminance projector and having a long life, and to provide the projector.
The light source device 110 is provided with: light source lamps 1A and 1B; a rotary support substrate 70 which has a rotary shaft 70ax located at nearly equal distances from positions where the light source lamps 1A and 1B are disposed, and rotatably supports the light source lamps 1A and 1B in a plane vertical to an illumination optical axis OC; a light synthesizing optical system 90 which has reflection planes of the same number of the light source lamps 1A and 1B, synthesizes the light beams from the light source lamps 1A and 1B and emits the light beams; and a rotationally driving part 700 having a function to periodically rotate the rotary support substrate 70 so that the light source lamp 1A may be moved to the position where the light source lamp 1B is disposed, and light source lamp 1B may be moved to the position where the light source lamp 1A is disposed.
Osamu Suzawa
Kazuhiko Miyasaka