In an anti-skid device of fit-in type, less time and effort are needed for adjusting the inner width of anti-skid bodies. The anti-skid device is such that two or more anti-skid bodies having a U-shaped cross-section are fitted therein with a tire of a car and arranged in circumferential direction of the tire so as to be connected with one another. An exterior part of each anti-skid body is provided with a contact member for contacting with an outside surface of the tire, while an interior part is provided with a contact member for contacting with an inside surface of the tire. The exterior part or the interior part of each anti-skid body is attached thereto with a shaft 7 along an axial direction of the tire T. The shaft can move forward and backward in the axial direction of the tire. The contact member 6 is provided at an inner end of the shaft. An elastic member 9 is provided to apply a forward movement force to the shaft attached thereto with the contact member. The contact member is pressed against the outside surface or the inside surface of the tire by an elastic force of the elastic member. The contact member moves forward by the elastic force of the elastic member when the outside surface or the inside surface of the tire moves to opposite side to the contact member. The contact member moves backward against the elastic force of the elastic member when the outside surface or the inside surface of the tire moves to the contact member side.