A heavy duty pneumatic tire comprising: a tread having at least three circumferential grooves (28, 28s, 28m) formed thereon; a pair of sidewalls each connected to an end of the tread; a pair of beads each located radially inward of the sidewall; a carcass located inward of the tread and the pair of sidewalls and extending on and between a first bead and a second bead out of the pair of beads; a reinforcing layer located radially inward of the tread; and a buffer layer located radially inward of the reinforcing layer and formed from a crosslinked rubber, wherein among the at least three circumferential grooves (28, 28s, 28m), a circumferential groove located on each outer side in an axial direction is a shoulder circumferential groove, the reinforcing layer includes a belt including a large number of belt cords (48, 48A, 48B, 48C) aligned with each other, the buffer layer is stacked on the carcass, each end of the buffer layer is located axially outward of an end of the belt, the belt includes a first belt ply stacked on the buffer layer, a second belt ply located radially outward of the first belt ply, and a third belt ply located radially outward of the second belt ply, the buffer layer includes a sheet portion and a pair of hump portions located axially outward of the sheet portion and thicker than the sheet portion, and each of the pair of hump portions has a maximum thickness (Tb) at an end of the first belt ply, characterized in that a nominal aspect ratio of the heavy duty pneumatic tire is not greater than 65%, the reinforcing layer further includes a band including a helically wound band cord (52, 52E, 52F), and the hump portion is integrated with the sheet portion. a tread having at least three circumferential grooves (28, 28s, 28m) formed thereon; a pair of sidewalls each connected to an end of the tread; a pair of beads each located radially inward of the sidewall; a carcass located inward of the tread and the pair of sidewalls and extending on and between a first bead and a second bead out of the pair of beads; a reinforcing layer located radially inward of the tread; and a buffer layer located radially inward of the reinforcing layer and formed from a crosslinked rubber, wherein among the at least three circumferential grooves (28, 28s, 28m), a circumferential groove located on each outer side in an axial direction is a shoulder circumferential groove, the reinforcing layer includes a belt including a large number of belt cords (48, 48A, 48B, 48C) aligned with each other, the buffer layer is stacked on the carcass, each end of the buffer layer is located axially outward of an end of the belt, the belt includes a first belt ply stacked on the buffer layer, a second belt ply located radially outward of the first belt ply, and a third belt ply located radially outward of the second belt ply, the buffer layer includes a sheet portion and a pair of hump portions located axially outward of the sheet portion and thicker than the sheet portion, and each of the pair of hump portions has a maximum thickness (Tb) at an end of the first belt ply, characterized in that a nominal aspect ratio of the heavy duty pneumatic tire is not greater than 65%, the reinforcing layer further includes a band including a helically wound band cord (52, 52E, 52F), and the hump portion is integrated with the sheet portion.