To make anti-skid bodies hard to shift against a tire, and to make connecting members which connect the anti-skid bodies with each other hard to be separated.

In the anti-skid device wherein the anti-skid bodies 1a, 1b, 1c are U-shaped fit to an outer periphery side of the tire T, connecting members 21, 22 with connectors are attached in both ends in the outside of the anti-skid bodies, the connecting members of the anti-skid bodies are connected to the connecting members of the adjoining anti-skid bodies by the connectors, and several numbers of anti-skid bodies are arranged over the entire periphery of the tire for connection into a ring; the connectors are provided with lock mechanisms for locking the connecting members to be in a connected state, the lock mechanisms are configured to be locked and unlocked according to movement of movable members 36, tensioners 41, 42 are arranged for pulling the movable members of the lock mechanisms toward the center of the tire by elastic force, the anti-skid bodies are pressed against the outer periphery of the tire by pulling the connecting members connected with the anti-skid bodies by the tensioners toward the center of the tire, and the movable members of the lock mechanisms are maintained in the locking position by the tensioners.