A projector includes a projection optical system configured to project an image on a screen, a size detecting section configured to detect a size of a region of the screen on which the image is projected, a size determining section configured to determine, on the basis of the size of the region detected by the size detecting section, a size of an object projected on the screen, and a projection control section configured to cause the projecting optical system to project the image including the object having the size determined by the size determining section.