A signal processing device includes a transformer simulator for simulating transfer characteristic of a transformer which changes in frequency characteristic depending on a load connected to the transformer and processing an input signal with the transfer characteristic to output the processed signal, and a load impedance simulator for simulating impedance characteristic of a predetermined load to output the impedance characteristic. The transformer simulator simulates the transfer characteristic of the transformer to which the load having the load impedance which is simulated by the load impedance simulator is connected.