A signal separating apparatus includes circuitry to separate a signal of interest and other signal other than the signal of interest from each other in accordance with spatial information on a plurality of sensors installed at locations different from each other. The circuitry sets a parameter based on a spread of a subspace of the signal of interest, determines a degree of separation that serves as an index indicative of whether the set parameter is appropriate, and separates the signal of interest and the other signal from each other using the degree of separation.