A sipe extending in a tire width direction is provided in a land part (block) of a tread shoulder region, and the sipe is configured to include a first sipe part, a second sipe part having a groove width larger than the first sipe part and a third sipe part larger than the second sipe part. The first sipe part is formed over the whole of a sipe length direction in an opening side region of the sipe and the whole of a sipe depth direction in an inner region on the side of a tire equator; the third sipe part is formed in an outer region on the side of a tread ground contact end in a sipe bottom part region; and the second sipe part is formed in a region between the first sipe part and the third sipe part.