A hydrogen-oxygen gas generator comprises an electrolytic bath (10A), a pair of electrodes composed of an anode member (2x) and cathode member (2y) both disposed in the bath, a power supply (34) for applying voltage between the anode and cathode members, vibratory mixing means (16) for vibratively mixing the electrolyte (14) in the bath, and gas collecting means for collecting the hydrogen-oxygen gas generated by the electrolysis using the electrolyte. The gas collecting means includes a lid member (10B) annexed to the electrolytic bath (10A) and a hydrogen-oxygen gas collecting pipe (10B'') connected to the hydrogen-oxygen gas output port (10B'). The vibratory mixing means (16) includes a vibrating motor (16d) vibrating at 10 Hz to 500 Hz and vibrating blades (16f) attached to a vibrating rod (16e) not rotatably but vibrating in the electrolytic bath interlockingly with the vibrating motor. The vibrating blades of the vibratory mixing member (16) are so arranged as to oppose the surfaces of the anode and cathode members (2x, 2y).