A heavy duty pneumatic tire comprising: on a tread surface, two or more circumferential grooves extending continuously in a tire circumferential direction; a plurality of transverse grooves opening to circumferential grooves, among the two or more circumferential grooves, that are adjacent in a tire width direction; and a block defined by the circumferential grooves and the transverse grooves and extending across a tire equatorial plane; wherein one or more shallow grooves (7-9, 14-15, 31-32) is formed in the block, each of the one or more shallow grooves (7-9, 14-15, 31-32) having an average groove depth that is shallower than a maximum groove depth of the circumferential grooves adjacent to the block; wherein at least one of the one or more shallow grooves (7-9, 14-15, 31-32) is a raised bottom shallow groove that is in communication, directly or via another one of the one or more shallow grooves (7-9, 14-15, 31-32), with at least one groove among the circumferential grooves and the transverse grooves adjacent to the block, extends in a direction intersecting the tire circumferential direction at least in a central portion of the block in the tire width direction, and has a groove depth that is shallower in the central portion of the block in the tire width direction than at an end of the raised bottom shallow groove in the tire width direction, characterised in that OTD / 3 ≤ a < OTD / 2, and a < b ≤ OTD / 2, where OTD is a maximum groove depth of the circumferential grooves adjacent to the block, a is a minimum groove depth of the raised bottom shallow groove in the central portion of the block in the tire width direction, and b is a maximum groove depth of the raised bottom shallow groove at the end of the raised bottom shallow groove in the tire width direction. on a tread surface, two or more circumferential grooves extending continuously in a tire circumferential direction; a plurality of transverse grooves opening to circumferential grooves, among the two or more circumferential grooves, that are adjacent in a tire width direction; and a block defined by the circumferential grooves and the transverse grooves and extending across a tire equatorial plane; two or more circumferential grooves extending continuously in a tire circumferential direction; a plurality of transverse grooves opening to circumferential grooves, among the two or more circumferential grooves, that are adjacent in a tire width direction; and a block defined by the circumferential grooves and the transverse grooves and extending across a tire equatorial plane; wherein one or more shallow grooves (7-9, 14-15, 31-32) is formed in the block, each of the one or more shallow grooves (7-9, 14-15, 31-32) having an average groove depth that is shallower than a maximum groove depth of the circumferential grooves adjacent to the block; wherein at least one of the one or more shallow grooves (7-9, 14-15, 31-32) is a raised bottom shallow groove that is in communication, directly or via another one of the one or more shallow grooves (7-9, 14-15, 31-32), with at least one groove among the circumferential grooves and the transverse grooves adjacent to the block, extends in a direction intersecting the tire circumferential direction at least in a central portion of the block in the tire width direction, and has a groove depth that is shallower in the central portion of the block in the tire width direction than at an end of the raised bottom shallow groove in the tire width direction, characterised in that OTD / 3 ≤ a < OTD / 2, and a < b ≤ OTD / 2, where OTD is a maximum groove depth of the circumferential grooves adjacent to the block, a is a minimum groove depth of the raised bottom shallow groove in the central portion of the block in the tire width direction, and b is a maximum groove depth of the raised bottom shallow groove at the end of the raised bottom shallow groove in the tire width direction.