POSITIONING DEVICE

This positioning device comprises: an upper unit having balls, a retainer part that retains the balls, and an upper plate part that is disposed above the retainer part and has a carried article mounted thereon; a lower unit having a lower plate part on which the upper unit is mounted, and a guide part that compartmentalizes a movement region of the upper unit on the lower plate part; and an inclining mechanism that causes a movement region to incline relative to a horizontal surface and guides the upper unit on which no carried article is mounted to a standard position positioned on the lower side of the incline.