A hinge assembly and a mobile terminal are disclosed. The hinge assembly can include: a torsion spring; a shaft, which penetrates through the torsion spring; a bushing, coupled to one end of the torsion spring and to one side of the shaft; a holder, which is coupled to the other end of the torsion spring, and which the shaft penetrates through; a sliding cam, which is coupled to the other side of the shaft, and which may move in linkage with the shaft; a fixed cam, which engages the sliding cam; a compression spring, which is positioned between the holder and the sliding cam, and which may place the sliding cam in close contact with the fixed cam; and a housing coupled to the holder and the fixed cam. Thus, the mobile terminal can be unfolded automatically using just a few number of parts without requiring energy consumption.