Optical sensor

An optical sensor, comprising:

• a contact member having light permeability and including a contact surface configured to come into contact with a target object;
• a support member supporting the contact member;
• an imaging element provided on the support member to image the contact surface from inside the contact member;
• and
• a first optical path forming mirror provided on the contact member and forming a first optical path inside the contact member, the first optical path configured to guide a light ray having a first emission angle from the contact surface to a first area that is a portion of the imaging element,
• wherein the imaging element is configured to
• receive, in the first area, the light ray from the first optical path;
• and
• receive, in a second area different from the first area, a light ray having a second emission angle different from the first emission angle and coming from the contact surface via a second optical path different from the first optical path.