A portable engine generator includes a power generation unit operating an engine to generate electricity and a negative pressure fuel cock using a negative pressure in a crank chamber as an operating negative pressure to supply fuel to the engine. The negative pressure fuel cock is located on a side opposite to a negative pressure take-out port of the crank chamber with respect to a position of the power generation unit when the portable gas-engine generator is turned over, and so as to be located at a position higher than the negative pressure take-out port when the portable gas-engine generator is in an upright posture.