Heavy duty pneumatic tire

A heavy duty pneumatic tire includes a tread portion (2) provided with a pair of shoulder main grooves (3) and at least a center main groove (4) between the shoulder main grooves to form a pair of middle portions (6). Each middle portion is provided with a middle sub groove (20), axially outer middle lateral grooves (21), and inner middle lateral grooves (22). The respective number of outer and inner middle lateral grooves is from 40 to 50 in each middle portion. Each of the outer and inner middle lateral grooves includes a shallow bottom part having a depth smaller than that of the shoulder and center main grooves. The shallow bottom part is provided with a groove bottom sipe (30) that extends along a longitudinal direction of each lateral groove and includes a first portion, and a second portion having a depth smaller than the first portion.