Disclosed is a control device of an internal combustion engine capable of improving emission characteristics of the internal combustion engine at the start-up. When an ECU for engine control controls injection during the exhaust stroke of a port-injection internal combustion engine, first fuel injection is carried out during a period t 1 to t 2 at a fuel-injection timing before actual stroke determination at the engine start-up as shown in, for example, FIG. 12(b) on the basis of a crank angle based on a memory, and the injected fuel is introduced to a cylinder during the actual stroke. If the fuel is not injected during a period of t 1N to t 3N of the subsequent exhaust stroke as indicated by a solid line, the cylinder blows out, and the rotation of the engine cannot be smoothed at the engine start-up. To avoid this, the ECU for engine control performs control such that the fuel injection can be carried out by clearing a flag (F_INJ) indicating completion of fuel injection as indicated by an alternate long and short dash line at a timing t JUD of determining a memory lapse in the crank angle.