The utility model provides an automatic plugging device. The automatic plugging device comprises a fixing seat for fixing a movable plugging connector. The fixing seat is connected with a push rod of a push rod driving mechanism in a floating manner. The fixing seat is also provided with a guiding structure which is used for guiding and aligning when the movable plugging connector comes near a fixed plugging connector. When the automatic plugging device is in use, the push rod of the push rod driving mechanism is stretched out to drive the fixing seat to move towards the fixed plugging connector; when the fixed seat comes near the fixed plugging connector, the guiding mechanism on the fixing seat plays a role in guiding and aligning; and the floating connection between the fixing seat and the push rod ensures the floating alignment when a slight error exists in the plugging of the movable plugging connector and the fixed plugging connector. Therefore, the plugging precision is further improved.