A laser beam irradiation apparatus (100, 100A-E) configured to irradiate a target, comprising: a plurality of laser light sources (10, 101-103) configured for emitting first laser beams, respectively; and a light-condensing optics system (20, 60) comprising an incident face (20a, 50a, 60a, 70a) configured for making the first laser beams incident thereon and performing an optical operation on the first laser beams to emit second laser beams associated with the first laser beams, respectively, wherein the plurality of laser light sources (10, 101-103) are configured to emit the first laser beams from different positions so that beam diameters of the first laser beams are expanded towards the incident face (20a, 50a, 60a, 70a) of the light-condensing optics system (20, 60), wherein each of the first laser beams when emitted from the plurality of laser light sources (10, 101-103) overlaps at least one of the other first laser beams on the incident face (20a, 50a, 60a, 70a) of the light-condensing optics system (20, 60), and wherein the light-condensing optics system (20, 60) is configured so that beam diameters of all the second laser beams when emitted from the light-condensing optics system (20, 60) are minimal on a target face of the target which is a plane defined to be orthogonal to an optical axis (22, 52, 62, 72) of the light-condensing optics system (20, 60), and a distance between a center of each of the second laser beams and the optical axis (22, 52, 62, 72) on the target face is smaller than a beam radius which is half a beam diameter of each of the second laser beams on the target face, the beam diameter on the target face being defined as a diameter of a circle encompassing 86% of the beam power, where the center of the circle being positioned at the geometric center of the beam profile; and wherein each of the first laser beams when emitted from the plurality of laser light sources (10, 101-103) overlaps all other first laser beams on the incident face (20a, 50a, 60a, 70a) of the light-condensing optics system (20, 60). a plurality of laser light sources (10, 101-103) configured for emitting first laser beams, respectively; and a light-condensing optics system (20, 60) comprising an incident face (20a, 50a, 60a, 70a) configured for making the first laser beams incident thereon and performing an optical operation on the first laser beams to emit second laser beams associated with the first laser beams, respectively, wherein the plurality of laser light sources (10, 101-103) are configured to emit the first laser beams from different positions so that beam diameters of the first laser beams are expanded towards the incident face (20a, 50a, 60a, 70a) of the light-condensing optics system (20, 60), wherein each of the first laser beams when emitted from the plurality of laser light sources (10, 101-103) overlaps at least one of the other first laser beams on the incident face (20a, 50a, 60a, 70a) of the light-condensing optics system (20, 60), and wherein the light-condensing optics system (20, 60) is configured so that beam diameters of all the second laser beams when emitted from the light-condensing optics system (20, 60) are minimal on a target face of the target which is a plane defined to be orthogonal to an optical axis (22, 52, 62, 72) of the light-condensing optics system (20, 60), and a distance between a center of each of the second laser beams and the optical axis (22, 52, 62, 72) on the target face is smaller than a beam radius which is half a beam diameter of each of the second laser beams on the target face, the beam diameter on the target face being defined as a diameter of a circle encompassing 86% of the beam power, where the center of the circle being positioned at the geometric center of the beam profile; and wherein each of the first laser beams when emitted from the plurality of laser light sources (10, 101-103) overlaps all other first laser beams on the incident face (20a, 50a, 60a, 70a) of the light-condensing optics system (20, 60).