A control device for an internal combustion engine including an engine main body, a fuel injection valve configured to inject fuel into a combustion chamber in the engine main body, and an intake device configured to change oxygen density in the combustion chamber by changing the state of intake pressure, intake temperature, and exhaust gas recirculation "EGR" gas amount, the control device comprising an electronic control unit configured to control the fuel injection valve to inject at least primary fuel and secondary fuel in this order and cause heat release twice in a stepwise manner in the combustion chamber such that a pattern of a pressure increase rate in the combustion chamber includes a first peak and a second peak occurring after the first peak, control an injection timing and an injection amount of each of the primary fuel and the secondary fuel such that a second peak value that is a peak value of the pressure increase rate at the second peak becomes higher than a first peak value that is a peak value of the pressure increase rate at the first peak, control the intake device such that the oxygen density in the combustion chamber is increased along with an increase in a load of the internal combustion engine, control the injection timing and the injection amount of each of the primary fuel and the secondary fuel such that a peak difference that is acquired by subtracting the first peak value from the second peak value is increased as the load of the internal combustion engine is increased, the electronic control unit is configured to inject pre-fuel before the injection of the primary fuel; the control device is characterized in that the electronic control unit is configured to control an injection amount of the pre-fuel to be increased such that a crank interval from a crank angle at which the pattern of the pressure increase rate in the combustion chamber has the first peak value, to a crank angle at which the pattern of the pressure increase rate in the combustion chamber has the second peak value is increased as a rotational speed of the internal combustion engine is increased, and wherein a phase of a pressure wave generated by a second heat release of the two heat releases is set to deviate from a phase of a pressure wave generated by a first heat release of the two heat releases. control the fuel injection valve to inject at least primary fuel and secondary fuel in this order and cause heat release twice in a stepwise manner in the combustion chamber such that a pattern of a pressure increase rate in the combustion chamber includes a first peak and a second peak occurring after the first peak, control an injection timing and an injection amount of each of the primary fuel and the secondary fuel such that a second peak value that is a peak value of the pressure increase rate at the second peak becomes higher than a first peak value that is a peak value of the pressure increase rate at the first peak, control the intake device such that the oxygen density in the combustion chamber is increased along with an increase in a load of the internal combustion engine, control the injection timing and the injection amount of each of the primary fuel and the secondary fuel such that a peak difference that is acquired by subtracting the first peak value from the second peak value is increased as the load of the internal combustion engine is increased, the electronic control unit is configured to inject pre-fuel before the injection of the primary fuel; the control device is characterized in that the electronic control unit is configured to control an injection amount of the pre-fuel to be increased such that a crank interval from a crank angle at which the pattern of the pressure increase rate in the combustion chamber has the first peak value, to a crank angle at which the pattern of the pressure increase rate in the combustion chamber has the second peak value is increased as a rotational speed of the internal combustion engine is increased, and wherein a phase of a pressure wave generated by a second heat release of the two heat releases is set to deviate from a phase of a pressure wave generated by a first heat release of the two heat releases.