Probing apparatus and probing method

There is provided a processing apparatus capable of modifying an existing processing apparatus having a single loading port to one having dual loading ports by providing an additional loading port without increasing a foot print thereof and also capable of realizing a complete automation of a wafer transfer by utilizing an existing automatic transfer line. The processing apparatus includes a loader chamber having: a first and a second loading ports positioned to be spaced apart from each other at the side of a prober chamber, each of the loading ports mounting thereon waters; a sub-chuck, disposed under the second loading port, for positioning the wafers; and a wafer transfer unit having a transfer arm for transferring the wafers between the sub-chuck and the prober chamber, the transfer arm being rotatable and movable vertically.