The present invention provides a pneumatic tire which can ensure the manipulate stability and effectively reduce the tire noise caused by the air column pipe resonance. Each grounding part (12a-12c) is disposed with horizontal tread groove (arc horizontal tread groove (13), The 1L-th word shape horizontal tread groove (14), the 2L-th horizontal tread groove (15)) with an opening at main groove (11a-11c) at one end and another end is stopped in a grounding part, and with different length, the groove width of the opening part of the horizontal tread groove (13-15) is set smaller than the groovewidth of the part at the grounding side.