Optical apparatus, scanning optical apparatus, and image forming apparatus

An optical apparatus, comprising:

• an optical element that includes a first surface and a second surface on both sides of the optical element, respectively, in a thickness direction of the optical element;
• a first supporter that is disposed on one end side of the optical element in a longitudinal direction of the optical element and supports the first surface or the second surface;
• a first pressing member that presses the optical element to a side of the first supporter;
• a second supporter that is disposed on another end side of the optical element in the longitudinal direction and supports a portion of the first surface on one end side of the optical element in a shorter direction of the optical element;
• a third supporter that is disposed on the other end side of the optical element in the longitudinal direction and supports a portion of the first surface or the second surface on another end side of the optical element in the shorter direction;
• and
• a presser that presses the optical element to a side of the second supporter and a side of the third supporter, wherein
• a pressing force of the presser is set to be larger than a pressing force of the first pressing member.