Cable modem device and method of assembling the same

There is discolsed a cable modem device capable of reducing unnecessary signals inputted into a circuit substrate which processes signals and signal terminals from the outside and unnecessary radiation generated by the circuit substrate, the device having a hexahedral shield case which shields a circuit substrate, and a plurality of terminals for use in input/output of the signals with respect to the circuit substrate. Each of the terminals has a noise filter function, and is fixed to the shield case.