The positions at which electrode pads are arranged can be made more flexible, and electrical interconnects to be installed can be reduced. In addition, the degree of integration of a chip increases, making it possible to realize a large-scale device (optical switch etc.). In an optical module of the present invention, an interposer (an electrical connection intermediary component with electrode pins attached onto upper and lower faces in an array) is laid over a chip that includes a device configured by using a planar lightwave circuit (PLC) fixed onto a fixing metal plate, and a control substrate for driving the device is laid over the interposer. These components are mechanically fixed by a fixing screw or the like, and the electrode pads of the chip and the control substrate are connected to each other via the interposer.