PURPOSE: To eliminate cracks by forming a siping whose one end is extended to a lug groove and which is formed on the land section arranged on a tread with an end section having a specified depth and a main section which is shallower than the end section and inclining the bottom section of these sections and connecting to each other.

CONSTITUTION: The tread T of a tire is provided with a plurality of peripheral direction grooves 10 to 12 in parallel with each other by which the land section is divided into a plurality of sections 20 to 23. A plurality of lug sections 30 and notches 31 are arranged so as to cross each peripheral direction grooves 10 to 12. In addition, at least the land section 23 is provided with a siping 40 at least one end of which is extended to a lug groove 30. In such structure, a siping 40 comprises tapered ends 40A and 40B having depth equal to the depth of the lug groove 30 next to itself or less and flat main sections 40C which are shallower than them. The bottom section is formed by inclining both ends 40A and 40B and the main sections and connecting them to each other.