A pneumatic tire comprises a tread portion with a land ratio of from 75% to 80%, the tread portion provided with crown main grooves having groove widths of 2.0-8.0 mm and groove depths of 15.0-20.0 mm, shoulder main grooves having groove widths of from 8.0-14.0 mm and groove depths of from 15.0-20.0 mm and lateral narrow grooves with groove widths of 0.6-2.0 mm and groove depths of 15.0-20.0 mm, wherein each main groove has a cross section including a groove bottom and groove walls, each groove wall includes an inner part and an outer part, the inner part has an inclination of not more than 1 degree with respect to a groove centerline, and the outer part has an inclination larger than that of the inner part.