To provide a fuel injection device for an outboard motor capable of dispensing with a vapor separator mounted in an engine cowling, increasing the cooling effect of the return fuel from a pressure regulator, and improving the layout.

A fuel tank T and a fuel injection valve J are connected by fuel piping D, and the fuel piping D is provided with a positive displacement high-pressure fuel pump 1. The intake-side fuel piping 2 communicating the high-pressure fuel pump 1 and the fuel tank T is provided with a priming pump M, and the discharge-side fuel piping 3 communicating the high-pressure fuel pump 1 and the fuel injection valve J, is provided with a pressure regulator R. The return fuel piping 4 of the pressure regulator R is connected to the fuel tank T. The accumulator piping B communicates the intake-side fuel piping 2 and the discharge-side fuel piping 3 over the high pressure fuel pump 1, and the accumulator piping B is provided with an accumulator 5 for accumulating and holding the pressurized fuel generated from the priming pump M.