A fatigue degree input unit inputs a fatigue degree of a user through use of a processing device, and writes an input value of the fatigue degree into a storage device. A recommended duration calculation unit reads the input value of the fatigue degree written by the fatigue degree input unit from the storage device. In accordance with the input value of the fatigue degree read from the storage device, the recommended duration calculation unit calculates a bath duration to be recommended to the user, as a recommended duration, through use of the processing device. A recommended duration informing unit informs the user of the recommended duration calculated by the recommended duration calculation unit, through an output device.