We demonstrated that an optimally designed pinhole camera can be used as an astronomical tool to observe the libration and apparent diameter change of the Moon at night. The libration and apparent diameter change of the Moon were observed using a handmade pinhole camera with a diameter of 0.65 mm and a focal length of 400 mm. It was found that the lunar mare with its characteristic pattern can be observed using this pinhole camera with a resolution of 2.5 arcmin. It was also found that the apparent diameter change of the Moon of about 10% can be observed with this pinhole camera. The pinhole camera used in this experiment is very useful as a handmade scientific educational material for learning the principles of optics and the movement of the Moon.