An aligner device includes a robot hand, a lifting mechanism, sensors, a misalignment calculating unit, an x-y misalignment correcting unit, and a θ misalignment correcting unit. The robot hand includes vertically aligned hand members each configured to hold a planar workpiece. The lifting mechanism moves planar workpieces transported by the robot hand up from and down to the hand members, respectively. Each of the sensors, vertically spaced apart from each other, has a downward sensor surface to capture the outline of a planar workpiece brought close to the sensor surface by the workpiece lifting mechanism. The misalignment calculating unit calculates, by using the images of the captured outline shapes of the planar workpieces, an amount of positional misalignment of each planar workpiece with a reference position in X, Y and θ directions. The X-Y misalignment correcting unit corrects the misalignment of each planar workpiece in the X and Y directions based on the amount of X-Y direction misalignment calculated by the misalignment calculating unit. The θ misalignment correcting unit corrects the misalignment of each planar workpiece in the θ direction based on the amount of θ misalignment of the planar workpiece.