Disclosed is an air-quality detection apparatus including a casing body including a bottom and a side wall, a first printed circuit board (PCB) disposed horizontally above the bottom, a second PCB disposed horizontally in a first region above the first PCB, a CO2 sensor mounted on the second PCB, a volatile organic compound (VOC) sensor mounted in a second region on the first PCB that is closer to the side wall than the first region, a third PCB, which is disposed horizontally at a position spaced further upwards apart from the bottom than the first PCB and at least a portion of which is disposed in a third region that does not overlap the first PCB when the bottom is viewed from above, a fourth PCB disposed horizontally above the second PCB and the third PCB, and a dust sensor mounted on the fourth PCB.