Pusher drive unit and test handler

A pusher drive unit and a test handler are provided. The pusher drive unit includes a driving block, a gas supplying module and a diaphragm. The driving block has an inner space with an open end corresponding to a pusher and a gas inlet communicating with the inner space. The gas supplying module is connected to the gas inlet. The diaphragm is formed a driving chamber and connected to the pusher. Based on the pressure of the gas introduced from the gas supplying module into the driving chamber, the driving chamber is deformed or restored while the pusher advances or retreats relative to the electronic accessory. A central region of the diaphragm is connected to the pusher, an edge region of the diaphragm is engaged to the driving chamber, and an intermediate region between the central region and the edge region is formed to have at least one curved portion.