PROBLEM TO BE SOLVED: To provide an apparatus for measuring a movable range in which a movable part of an object to be measured is not overlapped with the other part of the object to be measured when viewed from a sensor position, thereby high-precision measurement is achieved.SOLUTION: An apparatus for measuring a movable range is a sensor for acquiring a first distance image of an object to be measured from a first direction and a second distance image of the object to be measured from a second direction. The apparatus comprises a sensor and a processing device. The sensor is configured such that the first direction is set so that a movable part of the object to be measured is not overlapped with the other part of the object to be measured over the entire of the movable range related to a first measurement parameter concerning the movable range in the XY plane of the joint of the object to be measured when viewing an object to be measured in the first direction, and the second direction is set so that the movable part of the object to be measured is not overlapped with the other part of the object to be measured over the entire of the movable range related to a second measurement parameter concerning the movable range in the XY plane of the joint of the object to be measured when viewing an object to be measured in the second direction. The processing device calculates the movable range related to the first measurement item based on the first distance image, and calculates the movable range related to the second measurement parameter based on the second distance image.
