There is disclosed a method of efficiently rotating a specimen without hindrance to observation of the specimen. A specimen holder having a holder body and a specimen-holding member is used. The holder body has a hole in which a step surface is formed. The specimen-holding member is supported from the step surface in the hole of the holder body and positioned within the hole. Arc-shaped slots are formed in the step surface. The specimen-holding member has an opening that accommodates the specimen. The specimen-holding member also has a surrounding portion through which rod-like members extend. The rod-like members have lower-end portions inserted in the slots formed in the step surface. The rod-like members also have upper-end portions. The specimen-holding member holding the specimen is rotated by rotating the upper-end portions of the rod-like members.