The invention provides a thin key and a keyboard. The thin key is arranged on a bottom board. The thin key comprises a keycap, a lifting support mechanism and a connecting member. The keycap is disposed above the bottom board. The lifting support mechanism is connected to the bottom board and the keycap. When the keycap is pressed, the lifting support mechanism drives the keycap to get close to the bottom board in the descending direction. The connecting member is disposed between the keycap and the bottom board and can be provided with an elastic body. The elastic body is used for driving the keycap to leave the bottom board in an ascending direction opposite to the descending direction; or the key can further comprise an elastic member, which is connected to the connecting member and is used for driving the connecting member to drive the keycap to leave the bottom board in the ascending direction. The thin key is simple in structural design, small in size, and small in height-wise size, and accordingly the overall height of the key can be reduced and the thinning development of keyboards is benefited.