Provided is a starting-fuel supply device, including: a starting-fuel supply valve configured to automatically add a starting fuel to an air-fuel mixture generated by a carburetor; and a valve chamber for the starting-fuel supply valve, wherein a fuel in a fuel tank is allowed to move to an intake passage through the valve chamber for the starting-fuel supply valve with use of a manual pump configured to suck up the fuel in the fuel tank into a carburetor before start of an engine, and wherein the valve chamber is disposed at a position below the intake passage when the engine is in a stored state.