There is provided a sample holder capable of reducing positional deviation of a cartridge in the heightwise direction of a sample. The sample holder includes the cartridge and a holder base having a mounting portion for the cartridge. The mounting portion includes a placement surface, a first tilted surface, and a rotary drive mechanism for imparting a rotary force to the cartridge. The cartridge includes an opposing first tilted surface opposite to the first tilted surface of the mounting portion. As the rotary drive mechanism imparts the rotary force to the cartridge, the first tilted surface of the cartridge is pressed against the first tilted surface of the mounting portion, whereby the cartridge is pressed against the placement surface.