A stator of a rotary electrical machine for generating a rotating magnetic field when coils are energized through electricity supply wires (53u, 53v, 53w), the stator of the rotary electrical machine, comprising: a core unit configured by a plurality of core assemblies, around which wires are respectively wound to form the coils and which are arranged to form a ring shape, including low voltage side terminals, which connect first ends of the coils; and a bus ring formed into a ring shape so as to face the core unit, holding the electricity supply wires (53u, 53v, 53w), and attached to the core unit so as to connect second ends of the coils to the electricity supply wires (53u, 53v, 53w) by means of high voltage side terminals, wherein the plurality of core assemblies is engaged with the bus ring, and each terminal accommodating portion, which is formed into a container shape having a predetermined volume, is individually formed relative to each of the plurality of core assemblies at an external side of the coils in a state where the bus ring is attached to the core unit, and wherein each of the terminal accommodating portions is filled with an insulating resin material in a state where at least one of a connecting portion of the first end of each of the coils and each of the low voltage side terminals and a connecting portion of the second end of each of the coils and each of the high voltage side terminals is accommodated within each of the terminal accommodating portions, characterized in that a plurality of box portions, each of which is formed into a container shape and opens toward the bus ring, are respectively provided to the plurality of core assemblies so as to be attachable thereto and detachable therefrom, a plurality of closing portions, each of which closes an opening of each of the plurality of box portions, is formed at the bus ring at a circumference thereof, and the plurality of box portions respectively faces the plurality of closing portions, and thereby forming the terminal accommodating portions when the bus ring is attached to the core unit. a core unit configured by a plurality of core assemblies, around which wires are respectively wound to form the coils and which are arranged to form a ring shape, including low voltage side terminals, which connect first ends of the coils; and a bus ring formed into a ring shape so as to face the core unit, holding the electricity supply wires (53u, 53v, 53w), and attached to the core unit so as to connect second ends of the coils to the electricity supply wires (53u, 53v, 53w) by means of high voltage side terminals, wherein the plurality of core assemblies is engaged with the bus ring, and each terminal accommodating portion, which is formed into a container shape having a predetermined volume, is individually formed relative to each of the plurality of core assemblies at an external side of the coils in a state where the bus ring is attached to the core unit, and wherein each of the terminal accommodating portions is filled with an insulating resin material in a state where at least one of a connecting portion of the first end of each of the coils and each of the low voltage side terminals and a connecting portion of the second end of each of the coils and each of the high voltage side terminals is accommodated within each of the terminal accommodating portions, characterized in that a plurality of box portions, each of which is formed into a container shape and opens toward the bus ring, are respectively provided to the plurality of core assemblies so as to be attachable thereto and detachable therefrom, a plurality of closing portions, each of which closes an opening of each of the plurality of box portions, is formed at the bus ring at a circumference thereof, and the plurality of box portions respectively faces the plurality of closing portions, and thereby forming the terminal accommodating portions when the bus ring is attached to the core unit.