A lens driving device comprising: an auto-focusing driving part, a Hall device, a first position detection magnet, and a second position detection magnet, the auto-focusing driving part including: an auto-focusing coil part disposed at a periphery of a lens part; and an auto-focusing magnet part composed of four permanent magnets (122A-122D) and disposed separately from the auto-focusing coil part in a radial direction, the four permanent magnets (122A-122D) being magnetized in a short direction and disposed in a square frame shape; the auto-focusing driving part being configured to perform automatic focusing by moving an auto focus movable part including the auto-focusing coil part in a light axis direction with respect to an auto focus fixing part including the auto-focusing magnet part by utilizing a driving force of a voice coil motor composed of the auto-focusing coil part and the auto-focusing magnet part; the Hall device being disposed separately from the auto-focusing magnet part in the light axis direction at a positon corresponding to one diagonal part of the auto-focusing magnet part such that a detection direction coincides with the light axis direction; the first position detection magnet being disposed in proximity to the Hall device such that a magnetization direction coincides with the light axis direction; the second position detection magnet having a configuration similar to that of the first position detection magnet, and being disposed at a position point symmetrical with the first position detection magnet about the light axis direction, wherein: parts of the first position detection magnet and the auto-focusing magnet part which are close to each other have the same polarity; and parts of the second position detection magnet and the auto-focusing magnet part which are close to each other have the same polarity. an auto-focusing driving part, a Hall device, a first position detection magnet, and a second position detection magnet, the auto-focusing driving part including: an auto-focusing coil part disposed at a periphery of a lens part; and an auto-focusing magnet part composed of four permanent magnets (122A-122D) and disposed separately from the auto-focusing coil part in a radial direction, the four permanent magnets (122A-122D) being magnetized in a short direction and disposed in a square frame shape; an auto-focusing coil part disposed at a periphery of a lens part; and an auto-focusing magnet part composed of four permanent magnets (122A-122D) and disposed separately from the auto-focusing coil part in a radial direction, the four permanent magnets (122A-122D) being magnetized in a short direction and disposed in a square frame shape; the auto-focusing driving part being configured to perform automatic focusing by moving an auto focus movable part including the auto-focusing coil part in a light axis direction with respect to an auto focus fixing part including the auto-focusing magnet part by utilizing a driving force of a voice coil motor composed of the auto-focusing coil part and the auto-focusing magnet part; the Hall device being disposed separately from the auto-focusing magnet part in the light axis direction at a positon corresponding to one diagonal part of the auto-focusing magnet part such that a detection direction coincides with the light axis direction; the first position detection magnet being disposed in proximity to the Hall device such that a magnetization direction coincides with the light axis direction; the second position detection magnet having a configuration similar to that of the first position detection magnet, and being disposed at a position point symmetrical with the first position detection magnet about the light axis direction, wherein: parts of the first position detection magnet and the auto-focusing magnet part which are close to each other have the same polarity; and parts of the second position detection magnet and the auto-focusing magnet part which are close to each other have the same polarity. parts of the first position detection magnet and the auto-focusing magnet part which are close to each other have the same polarity; and parts of the second position detection magnet and the auto-focusing magnet part which are close to each other have the same polarity.