Medical control device and medical observation system using a different wavelength band than that of fluorescence of an observation target to control autofocus

A medical control device comprising

• circuitry configured to:
• control an operation of a light source device configured to emit excitation light in a first wavelength band and image light including a pattern image in a second wavelength band;
• acquire a frame of a captured image obtained by capturing an observation target irradiated with light emitted from the light source device that fluoresces in response to the excitation light to output light in a third wavelength band, the frame of the captured image including light components in the second and third wavelengths bands, the second and third wavelength bands being different;
• calculate, based on the pattern image of the second wavelength band in the frame of the captured image, an evaluation value used in an autofocus process that controls a focus position of an imaging device configured to generate the captured image;
• and
• perform the autofocus process based on the evaluation value.