A specific criterion for judging whether the resist heating effect will occur under given beam and resist conditions is proposed. The criterion is directly applicable to direct‐writing variably shaped electron‐beam systems and chain‐scission type resists. After studying the relationship between resist temperature and pattern deformation, it is hypothesized then verified experimentally that pattern deformation occurs when temperature at the shot edge point is higher than the glass transition temperature of the resist. Experiments revealed that chemically amplified resists are more resistant to the resist heating effect than chain‐scission type resists. Applying the hypothesis to resist temperature calculations, a constant figure was derived that represents the criterion for high‐throughput writing systems. The figure suggests the beam and resist conditions that are required for high‐throughput pattern writing without the resist heating effect.