The present disclosure relates to a prism device, comprising a prism assembly, and a holder connected to the prism assembly. The holder comprises a first end and a second end oppositely arranged, and the second end is connected to the prism assembly, the first end is used to provide a support point for the holder, and the second end is movable relative to the first end to adjust a spatial position of the prism assembly relative to the support point. It is not required to wear the prism assembly on the nose bridge by mean of using a holder to support the prism device, which reduces the weight on the wearer's nose bridge and relieve the discomfort caused by wearing objects. In addition, when the visual field changes with the movement of the head, it will not cause dizziness to the user.