A cleaning water supply device contains a mixing unit including a channel assembly and a circular valve member, wherein the channel assembly includes an inlet channel, an outlet channel, a through channel between the inlet and the outlet channels, and at least one intake communicating with the through channel; the valve member is installed in the through channel and includes a flexibly circular wing formed therein to abut against and close the through channel so that the intake is stopped communicating with the inlet channel and the outlet channel, and when the vacuum attraction generates in the through channel, the inlet and the outlet channels are opened; a storing unit connected with the channel assembly of the mixing unit and including a chamber to receive a cleaning fluid and an output tunnel communicating with the chamber and the intake.