A medical image processing device includes an image processor configured to: generate an output image by combining a first captured image obtained by capturing light from an observation target irradiated with light in a first wavelength band and a second captured image obtained by capturing fluorescence from the observation target irradiated with excitation light, with corresponding pixels; output a brightness signal value of a target pixel to be generated in the output image, as either a brightness signal value of a first corresponding pixel corresponding to the target pixel in the first captured image or a brightness signal value of a second corresponding pixel corresponding to the target pixel in the second captured image; and output a color difference signal value of the target pixel in the output image as a value generated by using the brightness signal value of the second corresponding pixel.