Ozone water production device

Provided is an ozone water production device capable of quickly converging the ozone concentration to a target concentration. After switching from the stop control to supply control, a control unit (80) executes the stop control when ozone concentration (C) is higher than a first threshold value (C1) via a drop inflection point lower than the target concentration (Cset). The first threshold value (C1) is a value between a minimum value (Cmin) and a target concentration (Cset) obtained on the basis of the target concentration (Cset) and the minimum value (Cmin), which is the ozone concentration corresponding to the drop inflection point. 本发明提供一种能够使臭氧浓度快速地收敛于目标浓度的臭氧水制造装置。控制部(80)在从停止控制切换为供给控制之后，当臭氧浓度C经由比目标浓度Cset低的下降拐点而比第一阈值C1升高时，执行停止控制。第一阈值C1是基于目标浓度Cset和与下降拐点对应的臭氧浓度即最小值Cmin而求出的、最小值Cmin与目标浓度Cset之间的值。