An aligner apparatus according to one or more embodiments may include a first rotating base, a second rotating base, and a detection apparatus. The first rotating base on which a wafer placed thereon rotates around a first rotation axis line. The second rotating base on which a wafer placed thereon rotates around a second rotation axis whose position is different from that of the first rotation axis line. The detection apparatus includes one sensor for detecting the edge of the wafer, and the detection range of the sensor includes the edge of the wafer placed on the first rotating base and the edge of the wafer placed on the second rotating base, and detects the edges of the two wafers.