PURPOSE: To provide a pneumatic tire for heavy load heightened in the discharging effect of a stone bitten into an auxiliary groove even in the case of having a pattern based on blocks formed by main grooves and auxiliary grooves.

CONSTITUTION: In a pneumatic tire for heavy load, the tread is provided with plural main grooves 2, and the mutually adjacent main grooves 2 are connected by auxiliary grooves 3 smaller in groove width and shallower in groove depth than the main grooves 2 so as to form numerous blocks 4 divided by the main grooves 2 and auxiliary grooves 3. The groove width of each auxiliary groove 3 is enlarged as it approaches the main groove 2. At least one side groove wall of the auxiliary groove 3 is provided with a ledge part 6, and the height of the ledge part 6 from the groove bottom is lowered as it approaches the main groove 2.