The invention relates to a lifting support device for a key, the key and a keyboard. The lifting support device comprises a first connection rod and a second connection rod. The first connection rod is provided with a first arm portion and a second arm portion, the first arm portion is provided with a first opening groove, and the second arm portion is provided with a first protrusion portion. The second connection rod is provided with a third arm portion and a fourth arm portion, the third arm portion is provided with a second protrusion portion, and the fourth arm portion is provided with a second opening groove. The second protrusion portion extends along a first direction and abuts against the first opening groove, and the first protrusion portion extends along a second direction and abuts against the second opening groove, so that the first connection rod is connected with the second connection rod and the first direction is opposite to the second direction. When the second protrusion portion abuts against the first opening groove and the first protrusion portion abuts against the second opening groove, the first connection rod and the second connection rod can pivot along a virtual axis, and the first direction and the second direction are vertical to the virtual axis respectively. By means of the design, the structure is simple, the assembly is convenient, machining and assembly complexities are reduced, and the material manufacture cost is decreased.