Microstereolithography is a technique or method for fabrication of microstructures like micromechanisms, microdevices, microchannels or microcatheters . It comprises on axis or off axis scanning of a liquid photopolymer resin with a focused laser beam spot and allowing the scanned portion of the resin to cure or solidify and form the microstructures. This invention relates particularly to a method and a scanner for three dimensional focused laser beam spot scanning in microstereolithography for fabrication of microstructures like micromechanisms, microdevices, microchannels or microcatheters.