Projection optical system and projection type display device

A projection optical system that projects an image on a reduction side to a magnification side,

• wherein the projection optical system does not include a reflecting surface having a power,
• the projection optical system consists of, in order from the magnification side to the reduction side along an optical path, a first optical system and a second optical system,
• an intermediate image is formed between the first optical system and the second optical system,
• the first optical system includes an optical path deflection surface which deflects an optical path,
• assuming that
• a radius of a maximum effective image circle on the reduction side is Imax,
• a distance on an optical axis from a lens surface closest to the magnification side in the first optical system to the optical path deflection surface is Ddef, and
• Ddef is a value at a wide-angle end in a case where the projection optical system is a variable magnification optical system,
• Conditional Expression (1) is satisfied, which is represented by
• 0.2
• <
• Imax
• /
• Ddef
• <
• 0.7
• .
• (
• 1
• )