A holding mechanism for holding an image display element to a prism includes: a first fixing member fixed to the prism by an adhesive; and a second fixing member, which is fixed to the first fixing member using a screw, and which has the image display element directly or indirectly fixed to the second fixing member. A protruding section is provided at the periphery of a hole to be used for the purpose of fixing using the screw, and at the time of fixing the second fixing member to the first fixing member using the screw, the first fixing member and the second fixing member are directly or indirectly brought into contact with each other at the protruding section such that deformation due to screwing of the screw does not generate within a bonding region of the first fixing member.