A purification unit for purifying air by a photocatalytic reaction includes a first light source which emits light; a first reflection plate which reflects the light emitted from the first light source; and a plurality of purification plates which cause the photocatalytic reaction by irradiation of the light emitted from the first light source. In this arrangement, at least one of the purification plates is disposed between the first reflection plate and the first light source, and the light emitted from the first light source is transmitted through the purification plate disposed between the first reflection plate and the first light source, and then is reflected on the first reflection plate for irradiation onto the purification plates.