To provide excellent drive stability on ice as sipe break trouble is prevented from occurring by a method wherein a number of composite sipes each having two or more sipes extending in directions different from each other are formed in a block formed at a tread form an independent composite sipe neither connected nor cross other composite sipe.

In a pneumatic tire for running on an ice snow road having a number of blocks 1 formed at a treat, a number of composite sipes 2 each having two sipes 21 and 22 extending in directions different from each other are formed in each block 1 and form an independent composite sipe which is neither connected nor cross other composite sipe 2. Each composite sipe 2 is a cross type composite sipe 2 having sipes 21 and 22 extending in a tire peripheral direction and the direction of a tire rotary axis. The composite sipes 2 having the same size as each other are arranged at the block 1 at equal intervals of a pitch P in a peripheral direction and arranged in such a state to be deviated by approximate 1/3 pitch between adjoining tows. This constitution prevents the occurrence of sipe breakage trouble and a chanking-out trouble of the block.