A control device for an internal combustion engine provided with an intake air pressure sensor and an airflow meter includes a calculation unit for calculating a fuel injection quantity on the basis of a negative pressure of intake air measured by the intake air pressure sensor when a cranking motor starts cranking the internal combustion engine, and a switching unit for switching to calculation of the fuel injection quantity on the basis of an intake air flow rate measured by the airflow meter when a change value in an actual intake air quantity becomes smaller than a reference value.