A heavy duty pneumatic tire includes a tread surface having, on at least a section thereof, a plurality of circumferential-direction grooves extending along a tread circumferential line and land portions defined either by the circumferential-direction grooves or by the circumferential-direction grooves and tread ground contact edges. The land portions include at least one partitioned land portion in which a plurality of narrow width-direction grooves extending in a tread width direction are provided. A prescribed internal pressure is at least 750 kPa. A depth of the circumferential-direction grooves, represented by H, satisfies a relationship 7 mm≤H≤13 mm. A tread circumferential-direction spacing of the narrow width-direction grooves, represented by W, satisfies a relationship 5 mm≤W≤20 mm.