Lens device

A lens device, comprising:

• a main body, comprising a long axis direction, a first end, a second end, and a first side and a second side opposite to each other, wherein the first end and the second end are respectively located at two opposite ends in the long axis direction, and the first side and the second side are parallel to the long axis direction;
• a positioning magnet group, disposed on the main body, the positioning magnet group comprising:
• a first positioning magnet, close to the first end and the first side;
• a second positioning magnet, close to the second end and the second side;
• and
• a fourth positioning magnet, located between the first positioning magnet and the second positioning magnet, and close to the second side;
• a shutter, movably disposed on the main body, the shutter comprising a third side and a fourth side opposite to each other, wherein the third side corresponds to the first side and the fourth side corresponds to the second side;
• and
• a fixed magnet group, disposed on the shutter, the fixed magnet group comprising:
• a first fixed magnet, close to the third side, the first fixed magnet attracting with the first positioning magnet;
• and
• a second fixed magnet, close to the fourth side, the second fixed magnet attracting with the second positioning magnet and repelling with the fourth positioning magnet.