Projection optical apparatus and projector

A projection optical apparatus comprising:

• a first lens group including a first optical axis;
• a first optical path deflector disposed at a demagnifying side of the first lens group;
• a second optical path deflector disposed at the demagnifying side of the first optical path deflector;
• a second lens group disposed at the demagnifying side of the second optical path deflector, the second lens group including a second optical axis which is substantially parallel to the first optical axis;
• a first lens barrel holding the first lens group;
• a second lens barrel holding the second lens group;
• and
• a frame holding the first optical path deflector and the second optical path deflector,
• wherein the frame includes a frame main body and a cover frame,
• the frame main body includes
• a lens barrel attachment part including a first opening in which the first lens barrel is fitted and a second opening in which the second lens barrel is fitted and
• a first side part and a second side part facing each other and extending in a direction along a plane containing both the first optical axis and a third optical axis between the first optical path deflector and the second optical path deflector, and
• the cover frame is disposed at an opposite side to a lens barrel attachment part side with respect to the first and second optical path deflectors, and includes an outer circumferential part fixed to the the first and second side parts.