ION EXCHANGER

An ion exchanger includes a housing, a tube member, and an ion exchange resin. The housing includes an inlet port and an outlet port. The tube member is arranged inside the housing. The ion exchange resin is arranged between the tube member and the housing. A first flow passage and a second flow passage are formed in the housing. The first flow passage is configured to cause the coolant that has flowed in through the inlet port to flow directly to the outlet port. The second flow passage is configured to cause the coolant that has flowed in through the inlet port and passed through the ion exchange resin to flow to the outlet port. The first flow passage and the second flow passage are formed to join together in a state of being oriented in a same direction toward the outlet port.