Disclosed is a laser scan type projector including laser light sources for three colors which alternately emits a laser light relating to an image for left eye and a laser light relating to an image for right eye on the basis of an image signal, a polarization switching unit which makes the laser light relating to the image for left eye and the laser light relating to the image for right eye, a first ¼ wavelength phase difference device which makes the two laser lights in which the polarization directions are switched by the polarization switching unit enter and which converts the polarization directions of the entered two laser lights so that each of the two laser lights be a circularly polarized light in an opposite direction from each other and a scan unit which scans a projection screen with the laser lights which are circularly polarized.