Abstract: In a three-dimensional printing method using a three-dimensional printer, a powder material is integrated on a partial area of a bed of the printer. A laser is irradiated to the integrated powder material based on a two-dimensional shape information of a manufactured structure, to sinter a two-dimensional structure and a first wall layer. The integrating and the irradiating are repeated, to form a three-dimensional structure and the first wall layer. The first wall layer is disposed to divide the partial area of the bed into a remaining area of the bed except for the partial area of the bed.