Fuel injection apparatus of an internal-combustion engine

To drive a fuel injection system to start an engine without using a battery. In a fuel injection apparatus of an internal-combustion engine provided with a fuel injection system and a power supply system for driving the fuel injection system, a single-phase AC generator (10) that is driven by external forces during startup, a half-wave rectifier (20) that performs half-wave rectification on the power generated by the AC generator, a capacitor (30) that stores power passed through the half-wave rectifier are used as the power supply system, and a self-pressurization plunger pump (50) that is electromagnetically driven by the power passed through the half-wave rectifier and capacitor is used as the fuel injection system. In this way, a battery as a power source to pressurize the fuel in advance during startup is not required and it is possible to achieve simplification, low cost and low pollution due to lead-free in the system.