An inverter type engine generator includes an alternator operable as a motor for starting an engine; a converter composed of a three-phase rectifying bridge circuit, converting three-phase alternating current output from the alternator into direct current, and operatable as a motor driver for driving the alternator when power is supplied from a power source; and a processor and a memory. The upper and lower three sets of elements of the three-phase rectifying bridge circuit of the converter are configured such that upper elements are configured from duty-controllable switching elements and thyristors connected in parallel therewith, and lower elements are configured from duty-controllable switching elements having diodes. The processor and the memory perform turning off the lower elements and controlling the duty of the thyristors while turning off the upper elements so that an output voltage of the three-phase rectifying bridge circuit is reduced, when a detected terminal voltage of the converter exceeds the target voltage.