To provide a filter circuit that reduces an induced current generated by external magnetic field noise occurring from an adjacent circuit, suppresses electromagnetic noise radiated from an inductor, and solves the problem wherein costs are increased in an IC and a transmitting device; and to provide an optical module having the filter circuit, the IC, a connector, the transmitting device, and a transmission system.

In the filter circuit formed by a passive element, such as a capacitative element and an inductor, the inductor for forming the filter circuit has a center axis in the vertical direction on the same plane and is composed of two coils having different center axis positions. In this case, the two coils are connected so that a signal current flowing in each the two coils eddies in the opposite rotation direction, and the induced current generated by the external magnetic field noise flows in the opposite direction.