PORTABLE WORKING MACHINE INCLUDING ENGINE WITH CARBURETOR AND FUEL SUPPLY CONTROL METHOD THEREOF

To optimize fuel supply of an engine with a carburetor (100, 250) during engine operation, a throttle opening degree detection sensor (26) detecting a throttle opening degree and a control unit (40) controlling a valve body (10, 230) variably controlling an opening degree of a fuel discharge part (8a) or a fuel supply passage (222) based on a map are included. The map includes a plurality of sections divided based on the throttle opening degree and an opening degree of the valve body (10, 230) set for each section. The opening degree of the valve body set for each section is the opening degree of the valve body at which the engine rotation speed is highest in each section. The control unit (40) controls an electric actuator (14, 232) driving the valve body (10, 230) to achieve the opening degree of the valve body set in a section to which the throttle opening degree detected by the throttle opening degree detection sensor (26) belongs out of the plurality of sections.