Provided are a first test substrate and a second test substrate opposing each other, a first test circuit testing a device under test and being disposed on a face of the first test substrate that faces the second test substrate, a second test circuit testing the device under test and being disposed on a face of the second test substrate that faces the first test substrate, and a sealing section that is formed by sealing a space between the first test substrate and the second test substrate to enclose the first test circuit and the second test circuit in a common space that is filled with coolant.