A wired circuit board can control characteristic impedance at connection points between wires of a suspension board with circuit and terminal portions of the wired circuit board connected thereto with a simple structure, to improve signal transmission efficiency even for fine pitch wiring or for high frequency signals. The wired circuit board includes a relay flexible wiring circuit board formed by a first wired circuit board including a first metal substrate, a first insulating base layer, a first conductor layer and a first insulating cover layer which is substantially identical in layer structure with the suspension board with circuit and a second wired circuit board connected with the first wired circuit board for connecting with a control circuit board. Since the suspension board with circuit and the first wired circuit board are rendered substantially identical in layer structure, both characteristic impedances at these connection points can be matched.