PURPOSE: To provide a slip preventing tool which can be easily attached/ removed to/from a tire without jacking up, can be easily handled not by a specialist but by an ordinary driver without using any special tool, and is provided with higher slip preventing effect.

CONSTITUTION: A slip preventing plate, which is divided into circular arcs and is coveringly mounted over a tire outer circumferential face, is provided with spike-shape projections 2 arranged on the outer circumferential tread face for preventing a slip, while the slip preventing plate and the spike-shape projections 2 are made of such material as metal, synthetic resin, and rubber, and a tire slip preventing tool consists of the slip preventing plates 1, 1a, a connecting member 5 which installs and fixes the slip preventing plates 1, 1a in the tire outer circumference part, and a fastening lever handle 6.