A medical instrument 1 includes image pickup means 10 incorporated in a medical instrument body 2 and movably provided in the medical instrument body that picks up an image of the object to be examined from an observation window 14, covering means 3 movably provided at the medical instrument body so as to cover the observation window and in which an opening portion 3a is formed, drive means 8 that drives the covering means or the image pickup means, and control means 5 that controls the drive means so as to drive the covering means or the image pickup means by synchronizing a timing for the image pickup means to pick up the object image with a timing at which the opening portion and the observation window match, and can thereby prevent sticking of deposits to the observation window and obtain a clear observation image.