A synchronous reluctance rotating electrical machine comprising: a shaft which rotates around a rotational axis line; and a rotor core (9 and 209) fixed to the shaft, in which cavity portions (11, 12, 13, 14, 211, 212, 213, 214, 215, and 216) are formed for each pole, each of the cavity portions (11, 12, 13, 14, 211, 212, 213, 214, 215, and 216) is formed to be curved such that its center in a circumferential direction is positioned innermost in a radial direction so as to be formed in a projected shape toward a radially inward direction, each of the cavity portions (11, 12, 13, 14, 211, 212, 213, 214, 215, and 216) forms a multilayer structure in the radial direction along a d-axis, and bridges (16, 17, 18, 19, 231, 232, 233, 234, 235, and 236) are respectively formed between ends of the cavity portions (11, 12, 13, 14, 211, 212, 213, 214, 215, and 216) and an outer circumferential surface (9a and 209a), characterized in that when a center of one pole in a circumferential direction is a pole center and an end of one pole in the circumferential direction is a pole end, wherein the d-axis is referred to as the pole center and a q-axis located at both of circumferential ends of 1/4 circumferential angular region is referred to as the pole end, one of the bridges (16, 17, 18, 19, 231, 232, 233, 234, 235, and 236) which is positioned closest to the pole end in the circumferential direction is an radially-outermost bridge (19 and 236), and the radially-outermost bridge (19 and 236) is formed such that a thickness of the radially-outermost bridge (19 and 236) becomes gradually thicker from the pole center toward the pole end, one of the bridges (16, 17, 18, 19, 231, 232, 233, 234, 235, and 236) which is positioned on the pole center side across one interposed bridge (18 and 235) from the radially-outermost bridge (19 and 236) is an intermediate bridge (17 and 234), the intermediate bridge (17 and 234) is formed such that a thickness of the intermediate bridge (17 and 234) becomes gradually thicker from the pole end toward the pole center, and thicknesses of two bridges (16, 18, 233, and 235), each of which is next to the intermediate bridge (17 and 234) in the radial direction, are set to be substantially uniform along the outer circumferential surface (9a and 209a) of the rotor core (9 and 209). a shaft which rotates around a rotational axis line; and a rotor core (9 and 209) fixed to the shaft, in which cavity portions (11, 12, 13, 14, 211, 212, 213, 214, 215, and 216) are formed for each pole, each of the cavity portions (11, 12, 13, 14, 211, 212, 213, 214, 215, and 216) is formed to be curved such that its center in a circumferential direction is positioned innermost in a radial direction so as to be formed in a projected shape toward a radially inward direction, each of the cavity portions (11, 12, 13, 14, 211, 212, 213, 214, 215, and 216) forms a multilayer structure in the radial direction along a d-axis, and bridges (16, 17, 18, 19, 231, 232, 233, 234, 235, and 236) are respectively formed between ends of the cavity portions (11, 12, 13, 14, 211, 212, 213, 214, 215, and 216) and an outer circumferential surface (9a and 209a), characterized in that when a center of one pole in a circumferential direction is a pole center and an end of one pole in the circumferential direction is a pole end, wherein the d-axis is referred to as the pole center and a q-axis located at both of circumferential ends of 1/4 circumferential angular region is referred to as the pole end, one of the bridges (16, 17, 18, 19, 231, 232, 233, 234, 235, and 236) which is positioned closest to the pole end in the circumferential direction is an radially-outermost bridge (19 and 236), and the radially-outermost bridge (19 and 236) is formed such that a thickness of the radially-outermost bridge (19 and 236) becomes gradually thicker from the pole center toward the pole end, one of the bridges (16, 17, 18, 19, 231, 232, 233, 234, 235, and 236) which is positioned on the pole center side across one interposed bridge (18 and 235) from the radially-outermost bridge (19 and 236) is an intermediate bridge (17 and 234), the intermediate bridge (17 and 234) is formed such that a thickness of the intermediate bridge (17 and 234) becomes gradually thicker from the pole end toward the pole center, and thicknesses of two bridges (16, 18, 233, and 235), each of which is next to the intermediate bridge (17 and 234) in the radial direction, are set to be substantially uniform along the outer circumferential surface (9a and 209a) of the rotor core (9 and 209).