Rotation operation input device and electronic apparatus that achieve both downsizing and good operation feeling

An electronic apparatus comprising:

• a rotation operation input device configured to perform setting in accordance with an operation on a rotation operation member;
• one or more memories that store instructions;
• and
• one or more processors that execute the instructions to perform control in accordance with the setting performed by the rotation operation input device,
• wherein the rotation operation input device comprises:
• (1) detected portions configured to rotate along with rotation of the rotation operation member;
• and
• (2) a detection unit an optical sensor configured to detect the detected portions and to detect a phase of the rotation operation member,
• wherein the detected portions are provided at a predetermined interval along an outer edge of the rotation operation member,
• wherein the outer edge of the rotation operation member is provided with a recess/protrusion part for continuously providing a clicking feel,
• wherein recess parts of the recess/protrusion part are each positioned between the detected portions, along a rotation direction of the rotation operation member,
• wherein protrusion parts of the recess/protrusion part are each positioned on each straight line connecting each detected portion and a rotation axis of the rotation operation member, and
• wherein (a) an urging member that urges the recess/protrusion part and (b) the detected portions are provided on opposite sides of the recess/protrusion part.