An atomic force microscope which can provide an automatic operation of focusing a laser beam onto a cantilever of the atomic force microscope, and which can ensure that a laser beam reflected off this cantilever is properly directed to a detector. A tip supported by the cantilever can also be automatically and properly lowered to a specimen. A piezotube scanner within such an atomic force microscope is also provided to prevent any damage from occurring if any leakage of an aqueous solution containing the specimen occurs.