A projector includes a power receiving terminal, a light source that emits light based on electric power supplied to the power receiving terminal, a light diffuser that adjusts the degree of diffusion of the light from the light source, a specifying section that alternately specifies one of illumination projection and image projection every time electric power supply to the power receiving terminal is started, and a light diffusion controller that controls the light diffuser so that when the specifying section specifies the illumination projection, the light diffuser diffuses the light from the light source, whereas when the specifying section specifies the image projection, the light diffuser transmits the light without substantially diffusing the light.