Lens drive device, camera module, and camera-mounting device

A lens driving device comprising:

• a lens driving device including an auto-focusing coil part disposed at a periphery of a lens part, and an auto-focusing magnet part disposed separately from the auto-focusing coil part in a radial direction, the lens driving device being configured to perform automatic focusing by moving, with respect to an auto focus fixing part including one of the auto-focusing coil part and the auto-focusing magnet part, an auto focus movable part including the other of the auto-focusing coil part and the auto-focusing magnet part in a light axis direction by use of a driving force of a voice coil motor composed of the auto-focusing coil part and the auto-focusing magnet part;
• and
• a position detection part disposed separately from the auto focus movable part on an imaging side in the light axis direction, the position detection part being configured to emit light toward the auto focus movable part and receive light reflected by the auto focus movable part to detect a position of the auto focus movable part in the light axis direction based on an intensity of received light, wherein:
• a part of a member that is displaced together with the auto focus movable part functions as a reflection plate configured to reflect light emitted from the position detection part.