Abstract: To facilitate positioning of a drill bit and alleviate burden to a user, a medical drill machine including a drive shaft gripping a drill bit, a casing constituted of X-ray transparent material and capable of housing the drive shaft, and a force transferring mechanism for transferring rotational force to the drive shaft is provided. In this medical drill machine, a first guide and a second guide constituted of X-ray opaque material are fixed at given positions along an axial direction of the drive shaft in the casing. Both guides are arranged coaxially with the axis of the drive shaft, and are formed in mutually different shapes. A slant direction of the drill bit can be recognized from any relative misalignment of the mutually different shapes of the guides included in an X-ray image along the ideal axial line.