Provided is a circuit board supporting structure capable of easily detaching a circuit board on a base. The circuit board supporting structure is configured to support a circuit board on a base, in which the base has a concave portion formed in a placement surface of the circuit board, and a rotational operation member configured to be rotatably accommodated in the concave portion and extend and retract in a direction perpendicular to the placement surface by a rotational operation, in which the circuit board has a through hole formed at a position corresponding to the concave portion, in which the rotational operation member has a reference surface formed approximately in parallel with the placement surface, and an operation portion formed on a rotational axis of the rotational operation member so as to be exposed from the through hole.