Provided is a pneumatic tire whose frictional force on ice is improved by satisfactorily forming resin-encapsulated cells from heat-expandable microcapsules, even when a tread rubber contains silica. The tire is characterized in that: the tread rubber is made of a rubber composition containing 100 parts by weight of a diene rubber, 30 to 100 parts by weight of a reinforcing filler including at least 10 parts by weight of silica, and 1 to 20 parts by weight of microcapsules each encapsulating a heat-expandable substance; a sulfur-containing silane coupling agent is mixed in the rubber composition in an amount of 3 to 15 wt. % based on the weight of the silica; a shell material of each microcapsule is made of a thermoplastic resin which essentially contains a nitrile monomer (I); a vapor pressure of the heat-expandable substance is set at 1.4 to 3.0 MPa at 150° C.; an average particle diameter of the microcapsules is set at 20 to 30 μm before vulcanization of the rubber composition; an average particle diameter of the microcapsules expanded due to the vulcanization is set at 40 to 80 μm; and thus, a proportion of an area occupied by the cells in the tread rubber is set at 5 to 30%.