There are provided a data processing device for chromatograph and a data processing method for chromatograph which allow a peak to be desirably checked. A peak (correction target peak (P1)) whose intensity exceeds a predetermined threshold in a chromatogram at a target wavelength (X1) is corrected based on correction reference values (height (H1) and area (A1) of a peak (P11)) and a sensitivity coefficient (R=I1/I2), and the chromatogram after correction is displayed or printed. Therefore, even if the correction target peak (P1) is saturated, display or printing may be performed in a state where correction has been performed so that the chromatogram at the peak (P1) is not cut off in the middle. Accordingly, at the time of display or printing of the chromatogram, a fine peak may be prevented from becoming too small, and also the correction target peak (P1) may be prevented from being cut off in the middle, and thus the peaks may be desirably checked.