A digital camera (10) includes a CCD imager (16). A long-time exposure image signal obtained by a long-time exposure of the CCD imager (16) is applied to a terminal (S1) of a switch (SW1), and a short-time exposure image signal obtained by a short-time exposure of the CCD imager (16) and a gain adjustment is applied to a terminal (S2) of a switch (SW2). A CPU (44) controls the switch (SW1) by comparing a Y level of the long-time exposure image signal with a reference value Ys so as to generate a combined image signal. More specifically, the CPU (44) connects the switch (SW1) with the terminal (S1) when a condition of Y level.ltoreq.Ys is satisfied, and connects the switch (SW1) with the terminal (S2) when a condition of Y level>Ys is satisfied. The CPU (44) detects a color deviation degree of an object prior to generation of the combined image signal and reduces the reference value Ys on the basis of a detection result. Therefore, the larger color deviation of the object is, the easier selecting of the short-time exposure image signal is.