A stator of a rotating electrical machine is provided. The stator includes a core unit which includes plural core assemblies arranged annularly, each core assembly being wound with a coil, plural accommodating portions which are provided to correspond to the core assemblies, each accommodating portion accommodating at least one of (i) a connection portion of end portions of adjacent coils for forming a neutral point and (ii) a connection portion of the other end portion of one of the adjacent coils and a power supply line, a temperature detector which detects at least one of a temperature of an oil and a temperature of a coil of the plural coils, and a signal line which is connected to the temperature detector for transmitting a detection signal from the temperature detector to an outside. Each of the accommodating portions includes a holding portion which holds the signal line.