The utility model discloses a car axle device which mainly comprises a mounting shaft end, a fixing pin and a connecting steel tube. The car axle device is characterized in that the connecting steel tube and the matched surface of the mounting shaft end after being processed are in clearance fit. The car axle device is realized as follows: a guide rail pulley is a transportation device frequently used in the manufacturing shop of a plant; when the body of the trolley is designed to be under light load, the shafts of each wheel can be designed independently; when the body of the trolley is designed to be under heavy load, the independent design of the body of the trolley can not meet the bearing requirements usually; in order to meet the requirements on the aspect of bearing and stop waste, the shafts are designed and processed by two parts, including the mounting shaft end and the connecting steel tube, which meets the requirements on the aspect of bearing of the shafts, but also controls the manufacturing cost.