A wafer carrier 1 includes a lower unit 2 on which a semiconductor wafer 100 is placed, and an upper unit 3 detachably attached to the lower unit 2, and forming a sealed chamber 4 for housing the semiconductor wafer 100 between the upper unit 3 and the lower unit 2. The upper unit 3 is provided with plural lock mechanisms 5 that fix the lower unit 2 to the upper unit 3 by abutting on a side surface of the lower unit 2.