In view of supplying a unified model of elementary particles the theory of relativistic rotators is developed. Clarifying the physical concept of relativistic rotators, general theory is constructed on the basis of kinematical variables. Consideration of the physical properties of the internal rotational space leads to the definition of isospin and internal chirality. Other internal constants of motion are also taken out to be identified as mass and ordinary spin. Possible rotator models are classified according to the structure of the rotational part of the Lagrangian. Various hitherto known models are automatically reproduced in this way, with their internal properties revealed. In addition, entirely new models also follow from this scheme.