An object is to prevent the color reproducibility of an observation image from decreasing, even when the peak wavelength is changed as a result of increasing or decreasing the amount of current supplied to a light source. Provided is an observation apparatus 1 including: a light source unit (11) that generates illumination light by using a plurality of solid-state illumination devices (19) to (21)； an image-acquisition device (8) that acquires an image of the illumination light generated by the light source unit (11) and reflected by an object； an image processing unit (18) that processes acquired image signals； and a control unit (26) that controls at least one of the light source unit (11) and the image processing unit (18). At least one of the solid-state illumination devices (20) has a peak in a G channel, another at least one of the solid-state illumination devices (19) has a peak in an R channel, and, when the control unit (26) increases the amount of the illumination light emitted from the light source unit 11, the control unit performs control so as to satisfy ”Sr / ”Sg >； 1, and, when the control unit reduces the amount of the illumination light emitted from the light source unit 11, the control unit performs control so as to satisfy ”Sr / ”Sg <； 1, where ”Sr and ”Sg are rates of change of system gains applied to the R channel and the G channel, respectively.
