Provided is a pneumatic tire capable of improving on-snow performance and anti-wear performance. A plurality of compound grooves 30 comprising horizontal grooves 31, one end of which connects to a principal groove 10 on one side thereof and the other end of which ends inside a rib 20, and further comprising sipes 32 extending from the other end of the horizontal grooves 31 to a principal groove 10 on the other side thereof, are formed at an interval from one another in the tire-circumferential direction in one or more rows of ribs 20 positioned inside a center region Ce. The compound grooves 30 are positioned in a manner such that the opening direction of the horizontal grooves 31 relative to the principal grooves 10 alternatingly reverses in the tire circumferential direction. A wide section 31a and a narrow section 31b are formed in each of the horizontal grooves 31. The ratio Wa/Wb of the groove width Wa of the wide section 31a to the groove width Wb of the narrow section 31b is in the range of 1.2-3.0, and the ratio Wb/Ws of the groove width Wb of the narrow section 31b to the groove width Ws of the sipes 32 is in the range of 1.2-5.0.