The invention relates to a rotor (2) of a thermal turbomachine, particularly of a gas turbine, having a number of individual rotor parts (6) that are held together by a tie rod (4) and combined into a unit, ensuring a reliable and safe operation, even at an increased installation length of the gas turbine. The natural frequency of the tie rod (4) is to be shifted toward higher frequencies in comparison to the rotational speed of the turbine. For this purpose the tie rod (4) is supported by the assembly of the surrounding rotor components consisting of the tie rod and the rotor disks. In combination with the two-part hollow shaft (11), the support wheel represents a further supporting rotor component.