To provide a mechanism for separating/stacking a stacking tray, a tray accommodation device provided with the mechanism and an IC test handler with a simple mechanism capable of vertically separating a plurality of loaded trays making a predetermined position as a border and stacking a raised tray on the tray placed below.

In the mechanism, a separation claw lever is inclinably provided on a lift part lifting along a tray accommodation frame. When the lifting part is ascended, the separation claw lever is retreated from the tray by a lever retreating means and is restricted by a lever restricting means. Further, when the lifting part is ascended and arrives at a predetermined height in the restricted state, it is released from the restriction by a lever restriction releasing means to be inclined to the tray side.