To stop movement of a patch member applied to a side face of a tire to an outer circumference side of the tire when the tire of an automobile rotates at high speed.

In the anti-skid device, anti-skid bodies are fitted in the tire and arranged to connect the outside parts of the anti-skid bodies, each of the anti-skid bodies includes front side and rear side U-shaped members and an inside linear member. In both the U-shaped members, inside parts are connected by the linear member, a front side and rear side connecting members are mounted to the outside parts, a connecting plate is interposed between the outside part of the U-shaped member and the connecting member, the outside patch member is provided at the outside connecting plate, a connecting plate is interposed between the inside parts of the U-shaped member and the linear member, and the inside patch member is provided at the inside connecting plate. Each of the connecting plates 11 and 13 includes an outer circumference side movement locking mechanism 61 for enabling the U-shaped members 2, 3 to rotate to the inner circumference side of the tire, disabling the members to rotate to the outer circumference side of the tire from the position of tire mounting, and locking movement of the patch members 16, 18 to the outer circumference side of the tire.