Atomic force microscope (AFM) is a powerful tool for exploring a nano-scale world. It can measure a nano-scale surface topography with very high resolution and detect a very small force. In this paper, we propose a novel AFM cantilever and its calibration scheme to utilize AFM as a mechanical testing machine. We call this AFM with a new cantilever as a force-calibrated AFM. The feasibility of the AFM cantilever is validated through measurement of mechanical properties of freestanding Au thin films.