A medical instrument is provided with: an illumination section radiating special light to a subject; an image pickup section acquiring return light generated on the basis of radiation of the special light; a frame rate setting section setting a frame rate of the image pickup section; and a charge reading control section controlling selection of pixels of the image pickup section to be read and a reading period on the basis of a value set by the frame rate setting section. The medical instrument enables adjustment of the frame rate while maintaining brightness of a picked-up image, so that missing of a site to be observed at the time of special-light observation is reduced.