A tester includes a level controller for independently restricting the central deformation and the peripheral deformation of a probe card. The level controller includes a single upper plate, a single first lower plate and a plurality of second lower plates. A first elastic force is applied to a central portion of the probe card by the first lower plate to restrict the central deformation. Second elastic forces are independently applied to peripheral portions of the probe card by the individual second lower plates to locally restrict the peripheral deformations.