To correctly measure the distance between the projecting point and the projected point of the projection light without being affected by the zooming magnification.

The projector control part 14 receives the information on the designated zoom magnification from the operation part 13. The projector control part 14 outputs the zoom designation signal to the optical mechanism part 25 from the acquired information on the zoom magnification, and also acquires the pitch (sensor pixel unit) for distance measurement drawn on the screen 2. The projector control part 14 set the window width (sensor pixel unit) so that the magnification number of the chart pitch in the distance measuring window becomes integer. The distance measuring sensors 31A and 31B receives light of a chart and determines the phase difference from the sensor pixel of the distance measuring window and measures the distance between the projector 1 and the screen 2 from the phase difference.