A turbine rotor blade assembly in which a plurality of turbine rotor blades are provided in a circumferential direction of a turbine disc, and the plurality of turbine rotor blades are adapted to be inclined in a predetermined direction during assembly whereas the plurality of turbine rotor blades are adapted to rise during rotation operation, the turbine rotor blade assembly comprising: platforms each including a blade root implanted in a blade groove provided on an outer peripheral surface of the turbine disc; profiles adapted to rise from the respective platforms; and shrouds provided at respective front ends of the profiles, said shrouds being further provided so as to face the respective platforms with the respective profiles in between; the turbine rotor blade assembly being characterized in that values A, CF, T, and L are set to satisfy the following expression, 1.2 × 10 5 ≤ A × CF / T × L ≤ 17 × 10 5, where A is the arm length [mm] of each of the turbine rotor blades and it is the distance from the rotation center to a gravity center of each of the turbine rotor blades, the rotation center of each of the turbine rotor blades is the rotation center when each of the turbine rotor blades receives the centrifugal force CF, thereby rising, CF is the centrifugal force [kgf] occurring on each of the turbine rotor blades during the rotation operation of the turbine rotor blade assembly, T is the thickness [mm] of each of the shrouds, and L is the lap amount [mm] of the shrouds adjacent to each other measured in the circumferential direction, and more specifically the lap amount L=P1-P2 wherein P1 is the pitch of each of the shrouds in the circumferential direction and P2 is the pitch of each of the shrouds in the circumferential direction in the rising state during operation. platforms each including a blade root implanted in a blade groove provided on an outer peripheral surface of the turbine disc; profiles adapted to rise from the respective platforms; and shrouds provided at respective front ends of the profiles, said shrouds being further provided so as to face the respective platforms with the respective profiles in between; the turbine rotor blade assembly being characterized in that values A, CF, T, and L are set to satisfy the following expression, 1.2 × 10 5 ≤ A × CF / T × L ≤ 17 × 10 5, where A is the arm length [mm] of each of the turbine rotor blades and it is the distance from the rotation center to a gravity center of each of the turbine rotor blades, the rotation center of each of the turbine rotor blades is the rotation center when each of the turbine rotor blades receives the centrifugal force CF, thereby rising, CF is the centrifugal force [kgf] occurring on each of the turbine rotor blades during the rotation operation of the turbine rotor blade assembly, T is the thickness [mm] of each of the shrouds, and L is the lap amount [mm] of the shrouds adjacent to each other measured in the circumferential direction, and more specifically the lap amount L=P1-P2 wherein P1 is the pitch of each of the shrouds in the circumferential direction and P2 is the pitch of each of the shrouds in the circumferential direction in the rising state during operation.