To provide a casting mold and a casting device, by which the strain of a polycrystalline silicon ingot formed by unidirectional solidification is reduced, and an ingot hardly generating cracks in a cutting process is obtained.

The casting mold 1 has a bottom plate 1a having a quadrangular shape, four side plates 1b each having such a trapezoidal shape that the lower base is longer than the upper base, an inner surface part comprising the bottom plate 1a and the four side plates 1b, which is formed by surrounding the outer periphery of the side faces of the bottom plate 1a with trapezoid upper bases, each having length corresponding to that of each side of the bottom plate 1a, forming an opening part by trapezoid lower bases, and fitting sides of the adjacent side plates to each other, eight ridge line parts where the bottom plate 1a contacts with four side plates 1b, and the four side plates 1b mutually contacts, and a releasing material layer provided on the inner surface part. In the casting mold 1, the taper angle of a reversed taper shape formed by each inner face of the side plates 1b is set to be ≥1° and ≤5°. The casting device is equipped with the casting mold 1 and a plurality of heat insulating members for the casting mold 1, which are arranged so as to surround the outer periphery of the casting mold 1 and to be separable in the vertical direction of the casting mold 1.