HEAT EXCHANGING VENTILATION DEVICE

A heat exchange ventilator includes an exterior casing including a supply air passage that lets a supply air flow through and an exhaust air passage that lets an exhaust air flow through, and a heat exchanger that is mounted between the supply air passage and the exhaust air passage to perform heat exchange between the supply air flow and the exhaust air flow and includes a heat exchange element of quadrangular-prism shape and heat exchanger frames each of which is mounted to each of four corners of the heat exchange element. The heat exchange ventilator includes a plurality of guide rails (18) that are mounted inside the exterior casing and engage the heat exchanger frame (22) to guide the heat exchanger that is attached to and detached from the exterior casing. Each of the guide rails (18) includes an end-face-facing part (18a) facing an end face (22a) of the heat exchanger frame (22), a side-facing part (18b) providing a clearance between a side (22b) of the heat exchanger frame (22) and the side-facing part (18b), a holding part (20) projecting from the side-facing part (18b) toward the heat exchanger frame (22), and a seal member (21) that is provided in the clearance and seals a gap between the heat exchanger frame (22) and the guide rail (18).