To provide an alignment device capable of preventing generation of abrasion of workpieces with each other and generation of internal stresses in the workpieces caused by the contact pressure even when the surface roughness and the relative parallelism of a holding face/a supporting face to hold and/or support an upper substrate workpiece and a lower substrate workpiece are low.

The alignment device comprises a holding device 201 capable of holding an upper substrate workpiece W1 and a supporting device 300 which is arranged below the holding device 201 and capable of supporting a lower substrate workpiece W2 in a substantially parallel manner to the upper substrate workpiece W1. The holding device 201 and/or the supporting device 300 are relatively moved in the x-axis direction and the y-axis direction by constituting a holding face 233 and a supporting face 310 in a relatively movable manner in the xy plane direction of each planar direction. The alignment device performs the relative positioning of the upper substrate workpiece W1 to the lower substrate workpiece W2. The holding device 201 can hold the upper substrate workpiece W1 in a separate and floating state with respect to the holding face 233.