To provide a common water regenerating device in which a common salt soln. is passed through a degraded ion exchange resin of a water softener to reactivate the resin.

In an ion exchange resin water softener for a common salt regenerating device used for the water softener by the ion exchange resin, in the case when hard water is softened, the hard water is passed through the ion exchange resin water softener and Ca++ and Mg++ being hard water components are adsorbed with the ion exchange resin to soften the water. It is necessary to regenerate and activate an adsorbing capacity by substituting Ca++ and Mg++ with Na ion by passing the common salt soln. through the ion exchange resin free from adsorbing capacity, that is, degraded ion exchange resin. In this case, the softener is provided with a two-direction changeover valve 16 changeovering a flow passage allowing the water to flow-in the vertical direction and a flow passage allowing the water to once flow-in the upper direction and then in the lower direction and an inverted vessel serving a changeover handle at an upper part of the two-direction changeover valve 16.