A heat exchange unit for a ventilation device includes: a case having a first inlet port through which first air is sucked and a second outlet port through which second air is discharged formed on a front side, and a first outlet port through which the first air is discharged and a second inlet port through which the second air is sucked formed on a back side; and heat exchangers having a first air passage through which the first air passes and a second air passage through which the second air passes formed thereon. A first separation plate for separating the first inlet port and the second outlet port is installed in the height direction on the front side of the case. A second separation plate for separating the second inlet port and the first outlet port is installed in the height direction on the other side of the case.