A marking device making a marking using laser beam, includes a supporting assembly, a marking mechanism, a carrying assembly, a driving assembly, and a plurality of loading members. The loading members carry workpieces for marking. The marking mechanism emits a laser beam to mark the workpiece. The carrying assembly includes a transmitting member slidably mounted on the supporting assembly, and a bearing member mounted on the supporting assembly opposite to the marking mechanism. The driving assembly is mounted on the supporting assembly. The loading members are placed on the transmitting member and the bearing member. The driving assembly is capable of driving the transmitting member to align with the bearing member in a straight line, and then driving the loading member on the transmitting member to move to the bearing member.