A probe card for high-frequency signal transmission includes a circuit board with transmission lines, a plurality of probes, and a signal path adjuster having first lead wires with a same length respectively connected between the transmission lines and the probes. Each first lead wire is selectively replaceable by a second lead having a length different from that of the first lead wire. As a result, a first high-frequency signal transmitting from one transmission line through the associated first lead wire to the associated probe and a second high-frequency signal transmitting from another transmission line through the associated second lead wire to the associated probe may have a same output timing when the first and second high-frequency signals are synchronously inputted into the circuit board.