Provided are a pixel interpolation apparatus, imaging apparatus, program, and integrated circuit that appropriately perform pixel interpolation on an image signal obtained by a single-chip image sensor with a four-color array filter whatever array pattern the four-color array filter has. An imaging apparatus includes an imaging circuitry, a signal processing circuitry, and a pixel interpolation processing circuitry. The apparatus calculates a degree of correlation for pairs in two orthogonal directions for an image signal obtained by the imaging circuitry including a single-chip image sensor having a four-color array filter using pixel data in an area around a target pixel, and performs pixel interpolation using the correlation degree as a determination criterion. When a color component pixel with a color identical to a color of a color component pixel subjected to pixel interpolation is not located in the direction having the high correlation, the pixel interpolation apparatus obtains a change ratio in a direction orthogonal to the direction having the high correlation by using a pixel value resulting from color space conversion in the direction orthogonal to the direction having the high correlation, and performs pixel interpolation processing based on the change ratio.