A signal processing device includes an electric connector to which a transmitting and receiving device, which transmits and receives a signal, is connectable; a first processor configured to compensate for, according to a setting value, deterioration of the signal input and output between the signal processing device and the transmitting and receiving device via the electric connector; a memory configured to store first characteristic data indicating a transmission characteristic of the signal in the electric connector; and a second processor configured to acquire, from the transmitting and receiving device, second characteristic data for indicating a transmission characteristic of the signal in the transmitting and receiving device and set the setting value in the first processor based on the first characteristic data and the second characteristic data.