The intermediate circuit board has a plate-shaped substrate and a plurality of signal transmission line pairs for differential signal transmission extending on a major face of the substrate from one end to the other end of the substrate in the direction of connection to the counterpart connect bodies; the substrate has a fiber cloth formed by braiding a plurality of fibers used to reinforce the substrate in a mesh pattern and a plate-like member made of plastic having the fiber cloth embedded therein; the plurality of signal transmission line pairs have straight pairs and cross pairs disposed in an alternating manner in the width direction of the substrate; and the straight pairs and cross pairs, when viewed in the through-thickness direction of the substrate, are formed extending inclined at an angle relative to the fibers of the fiber cloth.