The automatic corner sealing machine GPH-50 which is suitable for all types of cartons, after being sealed in the first half(upper cover), the carton is pushed by the L-shaped corner to seal the four corners. There is no need to manually adjust the size of the carton when the carton size changes, because the electric eye will automatically sense the carton, and then the cylinder can automatically move to adjust the carton size intelligently. The carton is driven by the upper and lower belts. It is fast and stable when sealing, and has no folds at the four corners.