An apparatus, which has a first air-passage channel, a second air-passage channel bifurcated from the first air-passage channel and an air-channel switching device that is provided in the apparatus and performs, for an air-passage channel in the apparatus, switching between the first air-passage channel and the second air-passage channel, the air-channel switching device comprising: an air-channel-switching-plate holding unit arranged near a bifurcation in the first air-passage channel substantially along a direction of an air current in the first air-passage channel; an air-channel switching plate that is turnably held by the air-channel-switching-plate holding unit and has a plate-like first section, a frame-shaped second section with an opening, and a plate-like third section connected to each other in a cranked form; and a driving mechanism that turns the air-channel switching plate such that, when the first air-passage channel is selected for the air-passage channel, the first section closes an inflow port of the second air-passage channel, the opening in the second section is positioned in a region of the first air-passage channel, the region being on a second air-passage channel side of the air-channel-switching-plate holding unit, and the third section is positioned on a downstream side of the air-channel-switching-plate holding unit, and when the second air-passage channel is selected for the air-passage channel, turns the air-channel switching plate such that the first section closes a region of the first air-passage channel, the region being on a side further away from the second air-passage channel than the air-channel-switching-plate holding unit, the opening in the second section overlaps on the air-channel-switching-plate holding unit, and the third section closes the region of the first air-passage channel, the region being on the second air-passage channel side of the air-channel-switching-plate holding unit. an air-channel-switching-plate holding unit arranged near a bifurcation in the first air-passage channel substantially along a direction of an air current in the first air-passage channel; an air-channel switching plate that is turnably held by the air-channel-switching-plate holding unit and has a plate-like first section, a frame-shaped second section with an opening, and a plate-like third section connected to each other in a cranked form; and a driving mechanism that turns the air-channel switching plate such that, when the first air-passage channel is selected for the air-passage channel, the first section closes an inflow port of the second air-passage channel, the opening in the second section is positioned in a region of the first air-passage channel, the region being on a second air-passage channel side of the air-channel-switching-plate holding unit, and the third section is positioned on a downstream side of the air-channel-switching-plate holding unit, and when the second air-passage channel is selected for the air-passage channel, turns the air-channel switching plate such that the first section closes a region of the first air-passage channel, the region being on a side further away from the second air-passage channel than the air-channel-switching-plate holding unit, the opening in the second section overlaps on the air-channel-switching-plate holding unit, and the third section closes the region of the first air-passage channel, the region being on the second air-passage channel side of the air-channel-switching-plate holding unit.