PURPOSE: To stably supply ozonized water with a specified concn. by adjusting the voltage value to be impressed on an ozonizer so that the ozonized water concn. is controlled to the target concn. set by a concn. setting means based on the detected ozonized water concn.

CONSTITUTION: This ozonized water generator 1 consists of a gaseous oxygen generating part 2, an ozonizer 3 and an ozonized water generating part. Concd. gaseous oxygen generated in the part 2 is supplied to the ozonizer 3, a voltage is impressed between the electrodes to generate a silent discharge, and ozone is generated. Gaseous ozone is absorbed in an ozonized water generating part 4 by the suction force of the water current accelerated in an ejector 13, and the ozone-contg. water is supplied to a gas-liq. separator 18. In this case, the concn. of the ozonized water is detected by a concn. meter 19, and the voltage value to be impressed on the ozonizer 3 is adjusted by a control circuit 29 based on the deviation of the detected value from the target concn. value set by a concn. setting device 31.