The liner bag for use in containers comprises a bag main body having bottom, side, front and upper faces corresponding to the configuration on the inner walls of a container, in which the joining edge between the upper face and the side face is bent convexly toward the opposed joining edge, engaging members for detachably engaging the bag main body near the upper and lower four corners on the front thereof to the container, a pair of engaging metal members attached respectively to the two upper corners on the container door side and a pair of side belts which are attached along the joining edges between the upper face and both of the side faces, the ends of which are led out from the ends of the upper face on the door side and in which the led out portions are clamped with each other after being engaged to the engaging metal members. The liner bag can easily be installed to and removed from the container and the sagging in the upper face of the liner bag can be prevented without reducing the volume thereof.