The Jones 2×2 matrix of the corner prisms is found. Various forms of the Michelson interferometer consisted of two corners are discussed. In the case that the beam in one arm passes through the edge of a corner and the beam in another arm does not pass through any edges of another corner, the interferometrio field is divided into two parts. The phase difference between these two parts is π/2 and the fringes contrast in the whole field is over 90%.