An internal combustion engine comprising: an intake passage through which air is guided to a combustion chamber; a fuel injection device through which a fuel is injected to the intake passage or the combustion chamber; at least one valve (38A,38B) disposed in the intake passage; and a controller that controls the valve (38A,38B), wherein the controller comprises: a first control section that keeps an opening of the valve (38A,38B) at an opening equal to or smaller than a first opening at least in a portion of an intake stroke of a first cycle; and a second control section that changes the opening of the valve (38A,38B) to a second opening greater than the first opening before end of an intake stroke of a second cycle subsequent to the first cycle, and keeps the opening of the valve (38A,38B) at the second opening at least in a portion of the intake stroke of the second cycle, characterized in that the controller comprises an ignition detection section that is adapted to detect fuel ignition in a first cycle at startup of the engine, and the second control section is configured to change the opening of the valve (38A,38B) to the second opening before the end of the intake stroke of the second cycle when fuel ignition is detected in the first cycle by the ignition detection section. an intake passage through which air is guided to a combustion chamber; a fuel injection device through which a fuel is injected to the intake passage or the combustion chamber; at least one valve (38A,38B) disposed in the intake passage; and a controller that controls the valve (38A,38B), wherein the controller comprises: a first control section that keeps an opening of the valve (38A,38B) at an opening equal to or smaller than a first opening at least in a portion of an intake stroke of a first cycle; and a second control section that changes the opening of the valve (38A,38B) to a second opening greater than the first opening before end of an intake stroke of a second cycle subsequent to the first cycle, and keeps the opening of the valve (38A,38B) at the second opening at least in a portion of the intake stroke of the second cycle, characterized in that the controller comprises an ignition detection section that is adapted to detect fuel ignition in a first cycle at startup of the engine, and the second control section is configured to change the opening of the valve (38A,38B) to the second opening before the end of the intake stroke of the second cycle when fuel ignition is detected in the first cycle by the ignition detection section. a first control section that keeps an opening of the valve (38A,38B) at an opening equal to or smaller than a first opening at least in a portion of an intake stroke of a first cycle; and a second control section that changes the opening of the valve (38A,38B) to a second opening greater than the first opening before end of an intake stroke of a second cycle subsequent to the first cycle, and keeps the opening of the valve (38A,38B) at the second opening at least in a portion of the intake stroke of the second cycle, characterized in that the controller comprises an ignition detection section that is adapted to detect fuel ignition in a first cycle at startup of the engine, and the second control section is configured to change the opening of the valve (38A,38B) to the second opening before the end of the intake stroke of the second cycle when fuel ignition is detected in the first cycle by the ignition detection section.