A sample holder according to an embodiment is a sample holder on which a sample to be observed with an electron microscope is mounted. The sample holder includes a support unit, a holder body, and a rotation mechanism. The support unit has a longitudinal direction and has a first end on which the sample can be mounted. The holder body holds the support unit at a second end on the opposite side from the first end. The rotation mechanism is provided inside the holder body and rotates the support unit with the longitudinal direction serving as an axis. A central axis of the holder body and a rotation axis of the support unit are axes in substantially same directions.