An optical circuit board which facilitates a mounting process and provides advantageous aspects of electric interconnection and optical interconnection. An optical circuit board comprises a flexible circuit board composed of a film having a flexibility; one or more electric interconnections provided at the flexible circuit board; one or more optical interconnections provided at the flexible circuit board; an optical transmitter for converting an electric signal supplied at a designated electric interconnection of the electric interconnections provided at the flexible circuit board into an optical signal; and an optical receiver for reconverting the optical signal emitted by the designated electric interconnection provided at the flexible circuit board into an electric signal and for outputting the reconverted electric signal to another electric interconnection.