A liquid container and its manufacturing method configured to contain a spring member and crimp a flexible member in a frame, wherein positional shift between the flexible member and the fixing member (frame) caused by compression of the spring during manufacturing process is prevented and no device is necessary for spring compression. Accordingly, the liquid container includes a liquid storage portion including a deformable flexible member, a planar portion disposed in the flexible member, and the spring member which abuts on the planar portion to generate negative pressure in the liquid container. The planar portion includes an engaging portion disposed in the planar portion and engaging the elastic portion so as to facilitate holding the elastic portion in a compressed state and releasing the elastic portion from the compressed state.