A stator of a rotary electrical machine includes a core unit configured by a plurality of core assemblies, around which wires are respectively wound to form the coils, including low voltage side terminals, which connect first ends of the coils, and a bus ring attached to the core unit so as to connect second ends of the coils to electricity supply wires by high voltage side terminals. Each terminal accommodating portion is individually formed relative to each of the core assemblies at an external side of the coils. 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 and each of the low voltage side terminals and a connecting portion of the second end and each of the high voltage side terminals is accommodated within each of the terminal accommodating portions.