To provide an ion exchange apparatus that can reduce useless cleaning operation as much as possible to further reduce an operation cost while securing sanitary treatment water.

The ion exchange apparatus includes: a circulating means 3 having: a water treatment mode for producing treatment water W2 by introducing raw water W1 into a pressure tank 2; a reproduction mode for reproducing an ion exchange resin bed 211 by introducing a regeneration liquid W4 into the pressure tank 2; a cleaning mode for cleaning the inside of the pressure tank 2 by introducing a cleaning liquid into the pressure tank 2; and a standby mode for not introducing a fluid into the pressure tank 2; a circulation detecting part 61 which can detect the presence of the circulation of the raw water W1 or the treatment water W2 into the pressure tank 2; a first timer means 52 for starting time measurement when the circulation detecting part 61 detects the absence of the circulation in a water treatment mode; and a circulation control means 51 for controlling the circulating means 3 to shift from the water treatment mode to the standby mode when reaches first predetermined time T3 by the first timer means 52.