This study simulates the sawing process with an abrasive circular saw blade and analyzes the generation of cutoff surfaces in the sawing process with the consideration of the blade deflection caused by the asymmetric wear of the blade outer edge. The analysis is built on the previous work of Matsui (1956, J. Jpn. Soc. Precis. Eng., 22, pp. 477–481) who presented an analytical formula for cutting force acting on a conical cutting edge. In this paper, the Matsui formula is modified to take into account the “size effect” of grinding and used to calculate the grinding force acting on the blade surface. A differential equation is constructed, and the related numerical solutions are provided to describe the blade deflection behavior in the sawing process. The study then discusses the influences of the “size effect,” workpiece length, workpiece speed and feed rate, as well as cutting edge density on sawing accuracies. Also discussed are workpiece speed and cutting edge density on the maximum deviation of the cutoff surface.