There is provided a composite structure including: at least two substrates which are made of thermoplastic resin and which are bonded by thermocompression; and at least one member which is made of a material whose heat distortion temperature is higher than a heat distortion temperature of the thermoplastic resin and which is inserted into a space formed in at least one of the substrates. The member inserted in the space is fixed and held by wall surfaces which form the space of the substrates and which are thermally deformed by thermocompression.