To provide a microbubble generator, which improves the efficiency of dissolving a gas into a liquid in a gas-liquid dissolving tank, while being reduced in size.

An inlet 12 of the gas-liquid dissolving tank 5 through which a gas-mixed liquid is supplied is provided in such a way as to face a liquid layer 10. The gas-mixed liquid is jetted in a divergent form toward a gas-liquid interface 17 from the inlet 12 through the liquid layer 10 to form a jet stream 14. The end of the jet stream 14 in the divergent form is allowed to reach a jetting zone 15 provided in one part of the gas-liquid interface 17. A non-jetting zone 16, which is adjacent to the jetting zone 15 and is not reached by the jet stream 14, and which has an area larger than that of the jetting zone 15, is provided over the entire periphery of the jetting zone 15 on the gas-liquid interface 17.