A projection type image display apparatus includes an optical engine that emits a light according to image signal, a Fresnel lens on which the light emitted by the optical engine is incident and emitting the light as a parallel light, and a diffusion member that diffuses the parallel light emitted by the Fresnel lens. The projection type image display apparatus further includes a driving unit that moves the Fresnel lens or the diffusion member in a plane parallel to an emitting surface of the Fresnel lens or the diffusion member, a frame the supports the Fresnel lens, the diffusion member and the driving unit, a resilient supporting body that supports a weight of the Fresnel lens or the diffusion member with respect to the frame, and a holding unit that holds the Fresnel lens or the diffusion member so as to be movable in the plane parallel to the emitting surface of the Fresnel lens or the diffusion member.