Abstract: A gas turbine blade assembly, which is as an assembly provided with a plurality of gas turbine blades on an outer circumferential surface of a rotating disk along a circumferential direction to be spaced apart from each other at predetermined intervals, includes: a retainer insertion hole provided in a blade-fixing end, and depressed by a predetermined depth to correspond to a lower end of a retainer; a retainer coupler provided at a lower end of each of the gas turbine blades, and depressed by a predetermined depth to correspond to an upper end of the retainer; and a coupling member coupled at a location adjacent to the retainer coupler to couple the retainer and each of the gas turbine blades together.