This invention discloses a laminator with a rolled paper sensing device, which comprises a machine body, a roller unit; at least one actuating element, sensor and guide. The machine body comprises an inlet, an internal accommodating space and an outlet, which are in communication with one another. Within the accommodating space, the roller unit is located which includes upper and lower rollers, and a channel between the upper and lower rollers leads to the inlet and the outlet; the actuating element is installed and positioned between the roller unit and the outlet; the sensor is located and adjacent to the actuating element; and the guide is located and in communication with the channel and the actuating element. Thus, the aim of sensing rolled paper of the laminator to avoid damaging the laminator and improve the utilization efficiency of the laminator is fulfilled.