A three-dimensional shaping method that includes lamination comprising alternately repeating a powder layer forming step and a sintering step in which the powder layer is sintered by irradiation of a moving laser beam or electron beam, wherein the following process is adopted during the sintering step: a. photographing a spark forming region generated with fly-off of powder caused by irradiation of a laser beam or electron beam over the entire periphery of the sintering region and measuring light intensity of the sparks, b. commanding to continue the sintering step for the next time unit or the next powder forming step, when, in a time unit within the time necessary for each sintering step, it has been detected that the width of the spark forming region photographed according to the process a and the light intensity of sparks measured according to the process a do not deviate from the respective ranges of the standard for the region width and the standard for the light intensity in which no sintering defect occurs, c. commanding to cancel the sintering step for the next time unit or the next powder forming step under judging that a sintering defect has occurred, when, in a time unit within the time necessary for each sintering step, it has been detected that the width of the spark forming region photographed according to the process a or the light intensity of sparks measured according to the process a deviates from the respective ranges of the standard for the region width or the standard for the light intensity in which no sintering defect occurs, characterised by d. photographing the spark forming regions at the sintering region in which a sintering defect that resulted in commanding of the process c was generated, and at the sintering region within the subsequent time unit, e. judging that the cause of the sintering defect that resulted in commanding in the process c is a problem with the control system related to the laser beam or electron beam, when each spark forming region width in the process d is unchanged or changes only gradually, and judging that the cause of the sintering defect that resulted in commanding in the process c is a problem with the powder layer surface, when each spark forming region width in the process d changes rapidly. a. photographing a spark forming region generated with fly-off of powder caused by irradiation of a laser beam or electron beam over the entire periphery of the sintering region and measuring light intensity of the sparks, b. commanding to continue the sintering step for the next time unit or the next powder forming step, when, in a time unit within the time necessary for each sintering step, it has been detected that the width of the spark forming region photographed according to the process a and the light intensity of sparks measured according to the process a do not deviate from the respective ranges of the standard for the region width and the standard for the light intensity in which no sintering defect occurs, c. commanding to cancel the sintering step for the next time unit or the next powder forming step under judging that a sintering defect has occurred, when, in a time unit within the time necessary for each sintering step, it has been detected that the width of the spark forming region photographed according to the process a or the light intensity of sparks measured according to the process a deviates from the respective ranges of the standard for the region width or the standard for the light intensity in which no sintering defect occurs, characterised by d. photographing the spark forming regions at the sintering region in which a sintering defect that resulted in commanding of the process c was generated, and at the sintering region within the subsequent time unit, e. judging that the cause of the sintering defect that resulted in commanding in the process c is a problem with the control system related to the laser beam or electron beam, when each spark forming region width in the process d is unchanged or changes only gradually, and