A clamping device includes a first holder and a second holder. The first holder includes a first abutting member and a driving member. The driving member is coupled to the first abutting member. The second holder includes a second abutting member. The first abutting member and the second abutting member are oppositely disposed and spaced apart from each other to receive a workpiece. The driving member is coupled to the first abutting member to drive the first abutting member to move in a direction toward the second abutting member to clamp the workpiece between the first abutting member and the second abutting member.