Softening device, method for regenerating softening device, and method for cleaning softening device

A softening device (1) is provided with a softening tank (3) and a neutralizing tank (4). The softening tank (3) softens raw water containing hard components by using a weakly acidic cation exchange resin (7). The water softening tank (3) has a first water softening tank (3a) and a second water softening tank (3b). The neutralization tank (4) neutralizes the pH of the softened water passing through the softening tank (3) by means of a weakly alkaline anion exchange resin (8). The neutralization tank (4) has a first neutralization tank (4a) and a second neutralization tank (4b). The water softening device (1) is configured so that raw water containing a hardness component flows through a first water softening tank (3a), a first neutralization tank (4a), a second water softening tank (3b), and a second neutralization tank (4b) in this order. 软水化装置(1)具备软水化槽(3)和中和槽(4)。软水化槽(3)利用弱酸性阳离子交换树脂(7)来将包含硬度成分的原水软水化。另外，软水化槽(3)具有第一软水化槽(3a)和第二软水化槽(3b)。中和槽(4)利用弱碱性阴离子交换树脂(8)来将通过软水化槽(3)之后的软水的pH中和。另外，中和槽(4)具有第一中和槽(4a)和第二中和槽(4b)。软水