An internal combustion engine comprising a controller, the internal combustion engine including: a combustion chamber; a sparkplug disposed in the vicinity of a center portion of an upper wall surface of the combustion chamber, the sparkplug being configured to ignite air-fuel mixture; an intake variable valve device being configured to change a lift amount of an intake valve; and a protrusion being provided on a wall surface of the combustion chamber for each of two intake ports, wherein tumble flow is generated inside a cylinder of the combustion chamber during lean burn operation, the controller comprising: an electronic control unit configured to change a shape of the tumble flow between a first tumble shape and a second tumble shape according to an engine rotation speed, wherein the electronic control unit is configured to control the intake variable valve device so that when the engine rotation speed is high, the lift amount of the intake valve is less compared with the lift amount of the intake valve when the engine rotation speed is low, characterized in that the protrusion is provided so as to surround an outlet of each of the intake ports, except a zone close to the sparkplug on central side of the combustion chamber, the first tumble shape being provided such that flow direction of gas around the sparkplug at the time of ignition of the internal combustion engine is direction from the intake valve side toward an exhaust valve side in a latter half of compression stroke, and the second tumble shape being provided such that the flow direction of the gas is reversed in the latter half of the compression stroke from the direction from the intake valve side toward the exhaust valve side to direction from the exhaust valve side toward the intake valve side due to change to the tumble flow having two swirling flow components with mutually opposite rotation directions, as viewed from above the combustion chamber, in a process in which an in-cylinder gas is compressed in the compression stroke, wherein the combination of the protrusion and the control of the intake variable valve device by the electronic control unit changes the shape of the tumble flow to the second tumble shape by increasing a ratio of flow rate of intake gas from each of the intake ports toward a center portion of the combustion chamber in the flow rate of the intake gas flowing into the combustion chamber in an intake stroke of the internal combustion engine. a combustion chamber; a sparkplug disposed in the vicinity of a center portion of an upper wall surface of the combustion chamber, the sparkplug being configured to ignite air-fuel mixture; an intake variable valve device being configured to change a lift amount of an intake valve; and a protrusion being provided on a wall surface of the combustion chamber for each of two intake ports, wherein tumble flow is generated inside a cylinder of the combustion chamber during lean burn operation, the controller comprising: an electronic control unit configured to change a shape of the tumble flow between a first tumble shape and a second tumble shape according to an engine rotation speed, wherein the electronic control unit is configured to control the intake variable valve device so that when the engine rotation speed is high, the lift amount of the intake valve is less compared with the lift amount of the intake valve when the engine rotation speed is low, an electronic control unit configured to change a shape of the tumble flow between a first tumble shape and a second tumble shape according to an engine rotation speed, wherein the electronic control unit is configured to control the intake variable valve device so that when the engine rotation speed is high, the lift amount of the intake valve is less compared with the lift amount of the intake valve when the engine rotation speed is low, characterized in that the protrusion is provided so as to surround an outlet of each of the intake ports, except a zone close to the sparkplug on central side of the combustion chamber, the first tumble shape being provided such that flow direction of gas around the sparkplug at the time of ignition of the internal combustion engine is direction from the intake valve side toward an exhaust valve side in a latter half of compression stroke, and the second tumble shape being provided such that the flow direction of the gas is reversed in the latter half of the compression stroke from the direction from the intake valve side toward the exhaust valve side to direction from the exhaust valve side toward the intake valve side due to change to the tumble flow having two swirling flow components with mutually opposite rotation directions, as viewed from above the combustion chamber, in a process in which an in-cylinder gas is compressed in the compression stroke, wherein the combination of the protrusion and the control of the intake variable valve device by the electronic control unit changes the shape of the tumble flow to the second tumble shape by increasing a ratio of flow rate of intake gas from each of the intake ports toward a center portion of the combustion chamber in the flow rate of the intake gas flowing into the combustion chamber in an intake stroke of the internal combustion engine.