A stereoscopic camera includes a master camera for photoelectric conversion of object light to generate a first image signal with three color components G, R and B. A slave camera generates a second image signal. In an adjusting method, a first gain Dmr, Dmg and Dmb of the color components is determined according to the first image signal to correct a brightness level and white balance of the master camera, to adjust the first image signal by use thereof. A second gain Dsr, Dsg and Dsb of the color components is determined according to the first gain and color calibration information predetermined according to color sensitivity of the master and slave cameras in relation to the color components. The second image signal is adjusted by use thereof, for color matching between the first and second image signals to set equal the brightness level and the white balance.