A probe card includes a space transformer, a printed circuit board and a plurality of welding elements. The space transformer is disposed with a plurality of first conductive protrusions. Each of thefirst conductive protrusions has a first end surface. The printed circuit board is disposed with a plurality of second conductive protrusions. Each of the second conductive protrusions has a second end surface. The welding elements are respectively and electrically connected between each of the second end surfaces and the corresponding first end surface. A first surface of the space transformer away from the printed circuit board has a first degree of flatness. A second surface of the printed circuit board away from the space transformer has a second degree of flatness. The first degree of flatness is less than the second degree of flatness.