A connector device to be used with a flexible printed circuit board including a connector. The flexible printed circuit board has on its front and rear surfaces ground patterns, signal patterns and phase inversion signal patterns arranged such that the signal pattern and the phase inversion signal pattern are arranged between the two ground patterns, and has a ground layer between the front and rear surfaces and exposed portions located at predetermined positions and reaching the ground layer. The connector has first and second contacts of two kinds. The first and second contacts are arranged in one and the same inserting hole of the housing such that their contact portions are opposite to each other. When a pivoting member has been pivotally moved, the first and second contacts come into contact with the corresponding ground, signal and phase inversion signal patterns on the flexible printed circuit board and the members at the predetermined positions enter the exposed portions so as to contact the ground layer, thereby achieving a miniaturization of the connector and high speed transmission of signals.