Summary. Internal variables are introduced in the framework of canonical thermomechanics on the material manifold. The canonical equations for energy and pseudomomentum cannot be separated by means of the scale separation because these equations should concern all fields together and, therefore, all scales together. However, the intrinsic interaction force requires a kinetic relation for internal variables. This kinetic relation depends on representation of the internal variable as "internal variable of state" or "internal degree of freedom".