A control apparatus for an internal combustion engine comprising: a supercharger that supercharges intake air of an internal combustion engine; a fuel injection valve capable of injecting fuel into a combustion chamber of the internal combustion engine; an ignition plug whose position relative to said fuel injection valve is set in such a way that fuel spray injected through said fuel injection valve passes through an ignition-capable region and the ignition plug can ignite the fuel spray directly; and a combustion control unit that is configured to perform first injection through said fuel injection valve at a first injection time during the compression stroke, ignites pre-spray formed by the first injection by said ignition plug, and starts to perform second injection through said fuel injection valve at a second injection time after the ignition of said pre-spray by said ignition plug and before the top dead center of the compression stroke with a predetermined first injection interval between said first injection time and said second injection time, said first injection interval being set in such a way that combustion of the fuel injected by said second injection is started by flame generated by ignition of said pre-spray, thereby causing self-ignition of fuel to occur and causing at least a portion of fuel injected by said second injection to be burned by diffusion combustion, wherein in a first operation state by which the engine load of the internal combustion engine is changed to a target engine load, said combustion control unit performs, in at least a part of a period until the actual boost pressure reaches a target boost pressure corresponding to said target engine load, first fuel injection control in which a first injection ratio, which is defined as the ratio of the fuel injection quantity in said first injection to the total fuel injection quantity in one combustion cycle, is made larger than a base first injection ratio, which is defined as the ratio of the fuel injection quantity in said first injection to the total fuel injection quantity in one combustion cycle in a second operation state in which the engine load of the internal combustion engine is equal to said target engine load and the actual boost pressure is equal to said target boost pressure. a supercharger that supercharges intake air of an internal combustion engine; a fuel injection valve capable of injecting fuel into a combustion chamber of the internal combustion engine; an ignition plug whose position relative to said fuel injection valve is set in such a way that fuel spray injected through said fuel injection valve passes through an ignition-capable region and the ignition plug can ignite the fuel spray directly; and a combustion control unit that is configured to perform first injection through said fuel injection valve at a first injection time during the compression stroke, ignites pre-spray formed by the first injection by said ignition plug, and starts to perform second injection through said fuel injection valve at a second injection time after the ignition of said pre-spray by said ignition plug and before the top dead center of the compression stroke with a predetermined first injection interval between said first injection time and said second injection time, said first injection interval being set in such a way that combustion of the fuel injected by said second injection is started by flame generated by ignition of said pre-spray, thereby causing self-ignition of fuel to occur and causing at least a portion of fuel injected by said second injection to be burned by diffusion combustion, wherein in a first operation state by which the engine load of the internal combustion engine is changed to a target engine load, said combustion control unit performs, in at least a part of a period until the actual boost pressure reaches a target boost pressure corresponding to said target engine load, first fuel injection control in which a first injection ratio, which is defined as the ratio of the fuel injection quantity in said first injection to the total fuel injection quantity in one combustion cycle, is made larger than a base first injection ratio, which is defined as the ratio of the fuel injection quantity in said first injection to the total fuel injection quantity in one combustion cycle in a second operation state in which the engine load of the internal combustion engine is equal to said target engine load and the actual boost pressure is equal to said target boost pressure.