Optical element, projection optical apparatus, and projector

An optical element comprising:

• a first light-transmissive member made of a first resin and having a first surface having an aspheric shape and a first joint surface provided on a side opposite from the first surface;
• a second light-transmissive member made of a material different from the material of the first light-transmissive member and having a second joint surface;
• and
• a first joining member and a second joining member that join the first joint surface and the second joint surface to each other,
• wherein the first joining member is made of a silicone adhesive and disposed in a smaller effective diameter region of the effective diameter region of the first light-transmissive member and the effective diameter region of the second light-transmissive member, and
• the second joining member is made of an adhesive having adhesiveness higher than the adhesiveness of the silicone adhesive and is disposed outside the first joining member and outside the smaller effective diameter region.