The present invention relates to a manufacturing method for fibrous demineralized bone matrix, the method comprising: (a) a step for subjecting a bone, separated from a body, to a primary demineralization in an acid solution for 1-5 hours (b) a step for slicing the bone obtained in step (a) to a thickness of 0.1-3mm, thus forming a sheet of bone (c) a step for subjecting the sheet of bone obtained in step (b) to a secondary demineralization in an acid solution for 2-6 hours and (d) a step for grinding the demineralized bone obtained in step (c).