The present invention provides a method for producing polylactic acid-based resin foamed particles for in-mold foam-molding from which a polylactic acid-based resin foam-molded article excellent in heat resistance and mechanical strength can be obtained by in-mold foam-molding. In the method of the present invention for producing polylactic acid-based resin foamed particles for in-mold foam-molding, a rotary blade is rotated at a given rotation speed while being always in contact with the front end surface of a nozzle and a polylactic acid-based resin extrudate extrusion-foamed through a nozzle is cut with the rotary blade, so that it is possible to cut the polylactic acid-based resin extrudate surely to obtain substantially spherical polylactic acid-based resin foamed particles. Therefore, when polylactic acid-based resin foamed particles are used for in-mold foam-molding, the polylactic acid-based resin foamed particles foam uniformly in all directions and, as a result, the foamed particles are thermal fusin bonded to unite together strongly in all direction.