This paper focuses on investigating friction behaviors in pre-sliding state and developing a new mathematical model of friction for pneumatic cylinders. Using pneumatic cylinders with different sizes, an experimental setup is made to measure friction force–displacement characteristics in pre-sliding state under various conditions of applied force and pressures in the cylinder chambers. A new mathematical model of friction is proposed by incorporating a hysteresis function into the new modified LuGre model. The friction behaviors of the pneumatic cylinders in pre-sliding state are clarified and the usefulness of the proposed mathematical model is verified through various experimental results.