A signal processing apparatus includes a signal processing section applying a spatial frequency filter to a pixel signal to perform a signal processing of noise reduction and/or edge enhancement, and a coefficient correcting section setting a coefficient group of the spatial frequency filter to a correct coefficient group. The coefficient correcting section includes an analyzing section, a correspondence section and a coefficient determining section. The analyzing section sets a local area to include an object pixel of the signal processing, and obtains average color information. A correspondence relation between the average color information and the correct coefficient group is set beforehand in the correspondence setting section. The coefficient determining section checks the correspondence relation of the correspondence setting section on the basis of the average color information obtained by the analyzing section, and adjusts the correct coefficient group used for the pixel of the processing object.