A pneumatic tire comprising: a tread portion having a ground contact surface, the tread portion being provided with a circumferentially extending shoulder main groove arranged proximate to a tread edge (Te) and a circumferentially extending crown main groove to form a middle land portion therebetween; the middle land portion being provided with a first middle lug groove extending axially inwardly from the shoulder main groove and terminating within the middle land portion; the first middle lug groove comprising a first groove wall and a second groove wall, the first groove wall comprising a protrusion protruding toward the second groove wall on the side of the shoulder main groove; the protrusion comprising a front wall located so as to form a sipe portion between the front wall and the second groove wall, a top wall, a first lateral wall located axially outward of the front wall and a second lateral wall located axially inward of the front wall, characterized in that the top wall comprises a step surface located radially inward of the ground contact surface of the tread portion and extending in parallel with the ground contact surface of the tread portion, the step surface configured to a triangular shape comprising a bottom side on the side of the first groove wall, a vertex protruding toward the second groove wall, a first oblique side extending from the vertex to an axially outer end of the bottom side and a second oblique side extending from the vertex to an axially inner end of the bottom side; the front wall configured to a triangular shape comprising a bottom side extending on a bottom of the first middle lug groove in parallel with the second groove wall, a first oblique side extending from the vertex to an axially outer end of the bottom side and a second oblique side extending from the vertex to an axially inner end of the bottom side; the first lateral wall extending between the first oblique side of the step surface and the first oblique side of the front wall; and the second lateral wall extending between the second oblique side of the step surface and the second oblique side of the front wall. a tread portion having a ground contact surface, the tread portion being provided with a circumferentially extending shoulder main groove arranged proximate to a tread edge (Te) and a circumferentially extending crown main groove to form a middle land portion therebetween; the middle land portion being provided with a first middle lug groove extending axially inwardly from the shoulder main groove and terminating within the middle land portion; the first middle lug groove comprising a first groove wall and a second groove wall, the first groove wall comprising a protrusion protruding toward the second groove wall on the side of the shoulder main groove; the protrusion comprising a front wall located so as to form a sipe portion between the front wall and the second groove wall, a top wall, a first lateral wall located axially outward of the front wall and a second lateral wall located axially inward of the front wall, characterized in that the top wall comprises a step surface located radially inward of the ground contact surface of the tread portion and extending in parallel with the ground contact surface of the tread portion, the step surface configured to a triangular shape comprising a bottom side on the side of the first groove wall, a vertex protruding toward the second groove wall, a first oblique side extending from the vertex to an axially outer end of the bottom side and a second oblique side extending from the vertex to an axially inner end of the bottom side; the front wall configured to a triangular shape comprising a bottom side extending on a bottom of the first middle lug groove in parallel with the second groove wall, a first oblique side extending from the vertex to an axially outer end of the bottom side and a second oblique side extending from the vertex to an axially inner end of the bottom side; the first lateral wall extending between the first oblique side of the step surface and the first oblique side of the front wall; and the second lateral wall extending between the second oblique side of the step surface and the second oblique side of the front wall.