A punching device includes a base, a linkage assembly, a carrying assembly, a punch and a pressure arm. The linkage assembly includes a pair of linkage members, a rotating member, a first connecting rod, a second connecting rod and a third connecting rod. The rotating member is rotatably mounted on the supporting member, the pair of linkage members is movably mounted on the rotating member, the first, the second and the third connecting rods connects in turn. The carrying assembly is rotatably connected to the third connecting rod and movably supported by the loading member. The punch is mounted on an end of the rotating member. The pressure arm is rotatably connected to the supporting member and the pair of linkage members to drives the carrying assembly to position a workpiece and the punch to punch the workpiece.