A starting device for feeding a quantity of fuel from the fixed-quantity fuel chamber to an intake passage during start-up having a manually operated primary pump for suctioning/pumping fuel and arranged on a fuel introduction path connected along a fuel-feeding path; and a fixed-quantity fuel chamber for temporarily storing fuel delivered from the primary pump. An internal wall of the fixed-quantity fuel chamber undergoes elastic displacement, allowing its internal capacity to expand/shrink within a predetermined range; the fixed-quantity fuel chamber is connected to a fuel delivery path that communicates with the intake passage side and has a manually operated open/close valve; the valve is opened in a state in which, due to the primary pump being operated, the fixed-quantity fuel chamber is filled with a predetermined quantity of fuel while enlarging its internal capacity, whereby it shrinks due to an elastic contraction force and the fuel.