To provide a pure water production apparatus which can surely perform the flow control of water supplied to an electric deionizing device of a fuel cell power generator by a simple structure.

The electric deionizing device 31 forms a desalination chamber 37 between a cation exchange membrane 34 and an anion exchange membrane 35, and forms a concentration and anode combining chamber 38 between the anion exchange membrane 35 and anode 33. A desalination chamber supply conduit 41 and a desalination chamber discharge conduit 42 are provided for the desalination chamber 37. A first solenoid valve 43 is provided for the terminal side of the desalination chamber discharge conduit 42, and a concentration chamber supply conduit 44 diverging before the solenoid valve 43, communicating to a concentration and cathode combining chamber 36, and being a concentration chamber water supply channel is provided. A second solenoid valve 45 is provided for the concentration chamber supply conduit 44. A pump 51 is provided on the way of the desalination chamber supply conduit 41, and a raw water tank 52 provided with a water gauge 53 is provided in the upstream of the pump 51.