1. An image capturing apparatus comprising an image sensor, said image sensor comprising a plurality of pixels arranged in the form of a matrix; signal amplifying means for amplifying pixel signals with amplification factors having a regular pattern set for said plurality of pixels, and pixel mixing means for mixing the pixel signals of the same colors amplified by said signal amplifying means, wherein said pixel mixing means mixes, on an R-G line which is a line in a horizontal direction or vertical direction of the matrix and on which R signals and G signals are alternately present, the R signals three pixels at a time and the G signals two pixels at a time, and mixes, on a G-B line which is a line in the horizontal direction or vertical direction of the matrix and on which G signals and B signals are alternately present, the G signals two pixels at a time and the B signals three pixels at a time.