To provide a projection type display apparatus that has a U-shaped configuration in which an illuminating optical system is bent by a mirror, the apparatus being designed such that thermal load is reduced and a mirror for bending light from a light source can be composed without a heat-resistant glass.

The projection type display apparatus bends light from the light source 1, composed of a lamp 1a and a parabolic metal reflector 1b, by the cold mirror 2, transmits the light to optical modulation elements 10B, 10G and 10R via fly eye integrators 3 and 4, and enlarges and projects the light, modulated by the optical modulation elements, by using a projection lens 20. In the projection type display apparatus, the cold mirror 2 is cooled by a current of cooling air from a fan 32. In addition, ultraviolet rays and infrared rays transmitted through the cold mirror 2 are emitted out of a cabinet 30. This prevents the ultraviolet rays and infrared rays from retro-reflecting toward the lamp 1a.