PROBLEM TO BE SOLVED: To provide a caster that automatically locks a wheel at the stage when a load begins to act and then automatically releases a lock state of the wheel when the load further increases.SOLUTION: This invention provides a caster, which comprises: a fork part for pivoting a wheel a bearing part that fits with a vertical shaft fixed on the fork part and is supported by the fork part so as to be slidable via an elastomer a braking body for braking the wheel and a link mechanism for transmitting an axial slide of the bearing part to the braking body, and which keeps the braking body in non-contact with a rotary part of the wheel when a load acting on the bearing part is a first magnitude, the braking body in contact with the rotary part of the wheel to brake the wheel when a load acting on the bearing part is a second magnitude greater than the first magnitude, and the braking body in non-contact with the rotary part of the wheel when a load acting on the bearing part is a third magnitude greater than the second magnitude.
