Abstract: An ion exchange device main body 3 includes: a tubular body 31 into which an ion exchange resin bag 5 accommodating the ion exchange resin is inserted through an opening and which has a liquid outlet 312 in which a liquid outlet port 314 for discharging an ion exchange target liquid to outside is formed; a lid 32 that is supported by the tubular body 31 and has a gas injection portion 324 in which a gas injection port 325 for injecting a to an inside 311 of the tubular body 31 is formed; a lead-out pipe 42 that is connected to the liquid outlet 312 and guides the ion exchange target liquid to the outside; and a check valve 44 that is provided in the lead-out pipe 42 and prevents the ion exchange target liquid from flowing backward from the outside to the inside.

Abstract: An ion exchange resin bag 5 includes a bag body 51 and a reinforcing body 52. The bag body 51 has a bottom surface portion 511 that is provided at an end portion opposite to an end portion where an opening is provided and forms a bottom surface of the bag body, and a side surface portion 512 that is connected to the bottom surface portion 511 and forms a side surface of the bag body 51. The reinforcing body 52 has a first reinforcing portion 521 that is fixed to a boundary portion of the bottom surface portion 511 and the side surface portion 512, and a second reinforcing portion 522 that is connected to the first reinforcing portion 521 and fixed to at least a part of the side surface portion 512 and extends from the first reinforcing portion 521 toward the opening.