Abstract: Provided is a probe card of a semiconductor testing apparatus, including a printed circuit board to which an electrical signal is applied from external, a space transformer having a plurality of probes directly contacting with a test object, and interconnectors connecting the printed circuit board to the probes of the space transformer. The space transformer includes substrate pieces which the probes are installed on one sides of, and a combination member joining and unifying the substrate pieces together so as to form a large-area substrate with the substrate pieces on the same plane. This probe card is advantageous to improving flatness even with a large area, as well as testing semiconductor chips formed on a wafer in a lump.