A control apparatus for a compression self-igniting internal combustion engine that performs combustion by self-ignition of fuel injected from a fuel injection valve into a cylinder, characterized by: target value setting means for performing setting in priority order of target values of a boost pressure of intake air, an exhaust gas recirculation rate, and a fuel injection timing such that an actual oxygen density inside the cylinder at a predetermined time after the fuel is injected, which is an end of a physical ignition delay period of fuel injected in a main injection, is adjusted using a target oxygen density inside the cylinder set in association with the predetermined time as a target value, wherein the target value setting means does not correct either the exhaust gas recirculation rate or the fuel injection timing in a case where the actual oxygen density matches the target oxygen density due to correction of the boost pressure of intake air to the target value, corrects the exhaust gas recirculation rate to the target value in a case where the actual oxygen density does not match the target oxygen density even with the correction of the boost pressure of intake air to the target value, does not correct the fuel injection timing in a case where the actual oxygen density matches the target oxygen density due to correction of the exhaust gas recirculation rate to the target value, and corrects the fuel injection timing to the target value in a case where the actual oxygen density does not match the target oxygen density even with the correction of the exhaust gas recirculation rate to the target value, and wherein the target value setting means sets the target value of the boost pressure of intake air such that the boost pressure of intake air is increased in a case where the actual oxygen density is lower than the target oxygen density, sets the target value of the exhaust gas recirculation rate such that the exhaust gas recirculation rate is reduced in a case where the actual oxygen density is lower than the target oxygen density, and sets the target value of the fuel injection timing such that a volume inside the cylinder at the predetermined time is reduced in a case where the actual oxygen density is lower than the target oxygen density. target value setting means for performing setting in priority order of target values of a boost pressure of intake air, an exhaust gas recirculation rate, and a fuel injection timing such that an actual oxygen density inside the cylinder at a predetermined time after the fuel is injected, which is an end of a physical ignition delay period of fuel injected in a main injection, is adjusted using a target oxygen density inside the cylinder set in association with the predetermined time as a target value, wherein the target value setting means does not correct either the exhaust gas recirculation rate or the fuel injection timing in a case where the actual oxygen density matches the target oxygen density due to correction of the boost pressure of intake air to the target value, corrects the exhaust gas recirculation rate to the target value in a case where the actual oxygen density does not match the target oxygen density even with the correction of the boost pressure of intake air to the target value, does not correct the fuel injection timing in a case where the actual oxygen density matches the target oxygen density due to correction of the exhaust gas recirculation rate to the target value, and corrects the fuel injection timing to the target value in a case where the actual oxygen density does not match the target oxygen density even with the correction of the exhaust gas recirculation rate to the target value, and wherein the target value setting means sets the target value of the boost pressure of intake air such that the boost pressure of intake air is increased in a case where the actual oxygen density is lower than the target oxygen density, sets the target value of the exhaust gas recirculation rate such that the exhaust gas recirculation rate is reduced in a case where the actual oxygen density is lower than the target oxygen density, and sets the target value of the fuel injection timing such that a volume inside the cylinder at the predetermined time is reduced in a case where the actual oxygen density is lower than the target oxygen density.