1. A computer-readable recording medium that stores therein a computer program that causes a computer to implement correcting a color balance of an image that includes a catch light area, the computer program causing the computer to execute: generating histograms of a gradation level of each pixel in the image for each color; identifying an area where a frequency of a gradation level of the histogram generated at the generating tends to decrease first starting from a highest gradation of the gradation level, as the catch light area, the identifying includes determining validity of the catch light area by checking whether a frequency of gradation level in frequency decreasing area of the catch light area is larger than a first predetermined threshold value for determining if there is a valid catch light area or not, and by checking whether a frequency of a gradation level in frequency decreasing area of the catch light area is smaller than a second predetermined threshold value; and calculating a correction amount of the color balance using pixels except for pixels included in the catch light area identified at the identifying.