The utility model provides a scalable temporary support device of face end is tunneled in pit in colliery, including main roof roof beam, scalable auxiliary girder, the compound back timber of strutting is constituteed to two hydraulic prop, planks and safe round pins, main roof roof beam and scalable auxiliary girder, and scalable auxiliary girder arranges the spout below the main roof roof beam in, safe round pin with the locking of scalable auxiliary girder in the spout of main roof roof beam, the plank setting is on scalable auxiliary girder, two hydraulic prop connect the lower part of main roof roof beam respectively, the utility model relates to a rationally, convenient to use, the last fixed plank of auxiliary girder have played and have increased the effect of strutting the area, have improved whole supporting device's stability simultaneously, and the hydraulic prop of scalable auxiliary girder below props up when establishing and retrieving, and the roof is in struts the state, has guaranteed the whole safety of strutting work.