Provided is an inexpensive device capable of accurately positioning a medical instrument relative to the head of a user. A head positioning device (7) is used. The head positioning device (7) is provided with: a pair of holding members (11, 12) which holds the face of a user from both sides by elasticity and prevents both the forward tilting of the users head and the rotation of the neck a neck rest (13) which comes into contact with the back side of the users neck and determines the position of the neck in the front-rear direction and a head-back rest (14) which comes into contact with the back of the head and which prevents the head from tilting backward.
