An analog/digital signal processor outputting analog input signals without eliminating copy protection signals from analog input signals, analog input signals having been subjected to copy protection process such as macrovision without adding complicated processes. The analog/digital signal processor for receiving input signals and outputting received input signals to a predetermined appliance through an analog or a digital communication unit, includes: a control unit determining whether the input signals are digital or analog signals and controlling a processing path and an output path of the input signals in accordance with the determination result; and a switching unit switching the input signals to the analog or the digital communication unit under the control of the control unit. When the input signals are analog signals, the control unit sets the processing path of the input signals to the switching unit and the switching unit switches the input signals to the analog communication unit.