The paper is aimed at the development of multi-valued holographic plane angle measure, so called, holographic prism. The holographic prism serves as a base of a device for calibration of equipment (swinging platforms) for navigation apparatus test on influence of rolling. The holographic prism is a small specimen of photosensitive material which a system of superimposed holographic gratings is written in, and a laser used for the gratings readout. Under the influence of the laser, a fan of diffracted beams is induced in the specimen. Consisting of the test device, the holographic prism is mounted on the platform, and while as it swings the fan moves along a photo-detector, for instance, CCD-sensor. First, fluorite was selected as a photosensitive material for the holographic prism. But it had several major drawbacks. Application of photothermo- refractive glass as the photo-sensitive material for the holographic prism manufacture permits to overcome these drawbacks. The hologram number is increased up to twenty-one. The fan proves to be very plane. The fan center is located in a domain which is of small size equal to some part of the specimen thickness (1-2 mm). The fan beams are energy-wise uniform, and every beam can be identified by using the fan in the test equipment. For instance, the beam can be coded, for its identification, by known angles between that beam and the adjacent ones. At last, the hologram recording in photothermo- refractive glass is much easier than that in fluorite.