An interface module for connecting LSI packages includes a connecting member which is to be mounted on an LSI package including an LSI chip and which includes lines to be electrically connected to the LSI package, an optoelectronic transducer which is mounted on the connecting member, which is connected to the lines of the connecting member, and which converts optical signal to electric signal or converts electric signal to optical signal, an optical waveguide which includes an optical input end and an optical output end, one of which is optically connected to the optoelectronic transducer, and a reinforcing film which is adhered to the optical waveguide, covering at least one side of the optical waveguide, and which is secured at one end to the connecting member.