The paper presents a thermomechanical analysis of a circular saw with the emphasis on the influence of thermal stresses on eigenmodes. Significance of the slot’s length was also investigated. The transient thermal analysis was carried out, and based on the obtained temperature field, the modal analysis was performed accounting for both thermal and centrifugal stresses. It was found that thermal stresses have a profound influence on eigenvalues. The results clearly indicate a necessity of performing analyses of this kind in order to obtain an efficient design of the circular saw. At the end, main findings are emphasized once more.