A wired circuit board is provided having excellent heat radiation characteristics, including when the semiconductor device is mounted on the wired circuit board by the flip chip mounting method. An insulating base layer defines a base opening portion in a mounting region. The base opening portion includes a thin layer portion that surrounds the base opening portion. Inside terminal portions are disposed on the thin layer portion. A heat radiating portion is formed in the base opening region to contact the stiffener sheet As a result, the surface of the inside terminal portion is located lower in level than the surface of the heat radiating portion. Thus, a semiconductor device may be mounted on the wired circuit board by the flip chip mounting method to enable heat generated from the semiconductor device to be transferred to the stiffener sheet via the heat radiating portion.