Provided is a handler apparatus that conveys a device under test to a test socket, including: an actuator that, prior to fitting of a device holder to the test socket, fits the device holder, and adjusts a position of the device under test on the device holder; and a conveyer that conveys the device holder in which a position of the device under test has been adjusted, to fit the test socket, where the device holder includes: an inner unit to mount the device under test; an outer unit to retain the inner unit to be movable; and a release button to release a lock of movement of the inner unit, in response to being pressed from a side to which the device under test is mounted, and the actuator sets the inner unit to be movable by pressing the release button and adjusts a position of the inner unit.