To provide a caster with its part hardly deformed or damaged even if excess torque is inputted to a wheel.

The caster 101 is provided with a caster body 103 mounted with the wheel, a caster holder 102 for rotatably supporting the caster body 103 around a rotation center line orthogonal to an axis of the wheel, and a slider 104 mounted to the caster holder 102 in a state of being movable between a position for being engaged with the caster body 103 so as not to relatively rotate around the rotation center line and a position for releasing the engagement with the caster body 103, and in a state of being incapable of relatively rotating around the rotation center line with respect to the caster holder 102. An engaging part of the slider 104 and the caster body 103 is provided with taper parts 104e, 106b, thus converting the torque inputted to the caster body 103 to a force directed to push away the slider 104 along the rotation center line.