Abstract: In an internal combustion engine system, a fuel injection control apparatus for preventing fuel leakage with high reliability in the engine-stopped state. The apparatus includes various types of sensors (5, 6, 14, 15) for detecting operation states of an internal combustion engine (1), a fuel pump (24) and a fuel supply pipe (22) for supplying a fuel from a fuel tank (23) to the engine (1), a fuel injector (8) for injecting the fuel into the engine, an engine stoppage detecting means for detecting a stopped state of the engine (1), a fuel temperature estimating means for estimating temperature of the fuel within the fuel supply pipe (22), and a fuel pressure lowering means for lowering pressure of the fuel within the fuel supply pipe (22). The fuel pressure lowering means is designed to lower pressure of the fuel within the fuel supply pipe (22) after the stoppage of operation of the engine (1) in dependence on an estimated fuel temperature determined by the fuel temperature estimating means.