A keyboard includes housing and two support members. The housing defines two receiving spaces each including a bottom defining a perforation. The two support members are received in the receiving spaces. Each support member includes an adjusting wheel and a support. The adjusting wheel is rotatably received in the receiving space and defines a spiral groove. The spiral groove includes spiral lateral surface. The support is received in the receiving spaces and aligned with the perforation, and includes a pin received in the spiral groove. When the adjusting wheels are rotated, the pins are urged by the spiral lateral surface to move, changing an inclination angle between the base and a support surface supporting the base.