A signal processing device includes a sound pickup unit configured to pick up sound and convert the sound into a sound signal; a signal recording unit including an actuator that is driven by a current supplied from a power source and that has a possibility of generating audible noise caused by the driving, the signal recording unit being configured to record the sound signal therein; a current detecting unit configured to detect the magnitude of the current and a temporal change in the current; and a signal processing unit configured to determine, on the basis of at least one of the magnitude of the current and the temporal change in the current, whether the audible noise has been generated and perform, when it is determined that the audible noise has been generated, noise removal processing for removing the audible noise from the sound signal, which contains the audible noise.