A medical instrument holding apparatus comprises a support arm supported such that it is rotatable about a first axis of rotation, a first arm supported such that it is rotatable about a second axis of rotation, a second arm supported such that it is rotatable about a third axis of rotation, and a third arm supported such that it is rotatable about a fourth axis of rotation. This apparatus further comprises first, second, third and fourth locks for locking the support arm, the first arm, the second arm and the third arm about the first, second, third and fourth axes of rotation, respectively, and for releasing the locked states of the arms. This apparatus can select control for causing predetermined three of the first, second, third and fourth locks to execute a locking operation, or control for causing all the locks to execute the locking operation.