A heavy duty pneumatic tire comprising: a tread portion comprising a plurality of blocks separated by a plurality of circumferentially extending main grooves and a plurality of lateral grooves; at least one of the blocks being provided with two axially extending sipes to divide the block into a first end portion, a second end portion and a middle portion between the first end portion and the second end portion; the first end portion comprising a first projected portion that protrudes outwardly in a block-width direction from the middle portion so as to form a steplike side; and the second end portion comprising a second projected portion that protrudes outwardly in an opposite block-width direction to the first projected portion from the middle portion so as to form a steplike side, the first end portion further comprises a first non-projected portion on an axially opposite side of the first projected portion, and the first non-projected portion does not protrude outwardly from the middle portion in the block-width direction, and the second end portion further comprises a second non-projected portion on an axially opposite side of the second projected portion, and the second non-projected portion does not protrude from the middle portion in the block-width direction, wherein in a plan view of the tread portion, the middle portion has a pair of side edges each facing each of the main grooves, the pair of side edges are inclined in the same direction, and each of the first projected portion and the second projected portion has an edge (37a,38a) inclined in the same direction to the side edges, characterized in that the first non-projected portion is inclined in an opposite direction to the side edges of the middle portion, and the second non-projected portion is inclined in an opposite direction to the side edges of the middle portion. a tread portion comprising a plurality of blocks separated by a plurality of circumferentially extending main grooves and a plurality of lateral grooves; at least one of the blocks being provided with two axially extending sipes to divide the block into a first end portion, a second end portion and a middle portion between the first end portion and the second end portion; the first end portion comprising a first projected portion that protrudes outwardly in a block-width direction from the middle portion so as to form a steplike side; and the second end portion comprising a second projected portion that protrudes outwardly in an opposite block-width direction to the first projected portion from the middle portion so as to form a steplike side, the first end portion further comprises a first non-projected portion on an axially opposite side of the first projected portion, and the first non-projected portion does not protrude outwardly from the middle portion in the block-width direction, and the second end portion further comprises a second non-projected portion on an axially opposite side of the second projected portion, and the second non-projected portion does not protrude from the middle portion in the block-width direction, wherein in a plan view of the tread portion, the middle portion has a pair of side edges each facing each of the main grooves, the pair of side edges are inclined in the same direction, and each of the first projected portion and the second projected portion has an edge (37a,38a) inclined in the same direction to the side edges, characterized in that the first non-projected portion is inclined in an opposite direction to the side edges of the middle portion, and the second non-projected portion is inclined in an opposite direction to the side edges of the middle portion.