A method of forming a decorative layer on an outer surface of a tubular body having a cylindrical or tapered cylindrical shape in a prescribed portion of the tubular body, wherein the decorative layer has a lattice-like pattern in which first regions of a first color and second regions of a second color different from the first color are alternately arranged in an axial direction and a circumferential direction of the tubular body, wherein the decorative layer includes axial-direction decorative rows (R1, R2, R3, R4,...) arranged in the circumferential direction of the tubular body, each of the axial-direction decorative rows includes the first regions having a first prescribed shape and the second regions having a second prescribed shape that are alternately arranged along the axial direction of the tubular body, and the second regions in each axial-direction decorative row (R1, R2, R3, R4,...) are formed such that the first region in one axial-direction decorative row (R1, R2, R3, R4,...) is partially situated between two axially-adjacent first regions in a next axial-direction decorative row adjacent to the one axial-direction decorative row (R1, R2, R3, R4,...) in the circumferential direction with the second regions interposed therebetween, wherein the method comprises: rotatably supporting the tubular body; forming one row or two or more axial-direction decorative rows (R1, R2, R3, R4...) of said decorative layer including said first and second regions (30, 32) by discharging ink onto an outer surface of the tubular body over a predetermined angle in the circumferential direction of the tubular body while moving a printer head that has a plurality of nozzles for discharging ink in a generally axial direction of the tubular body throughout the prescribed portion; rotating the tubular body by the predetermined angle; and forming one subsequent row or two or more subsequent axial-direction decorative rows (R1, R2, R3, R4...) of said decorative layer including said first and second regions (30, 32) by discharging ink onto an outer surface of the tubular body over the predetermined angle in the circumferential direction of the tubular body while moving again the printer head in the generally axial direction of the tubular body throughout the prescribed portion. rotatably supporting the tubular body; forming one row or two or more axial-direction decorative rows (R1, R2, R3, R4...) of said decorative layer including said first and second regions (30, 32) by discharging ink onto an outer surface of the tubular body over a predetermined angle in the circumferential direction of the tubular body while moving a printer head that has a plurality of nozzles for discharging ink in a generally axial direction of the tubular body throughout the prescribed portion; rotating the tubular body by the predetermined angle; and forming one subsequent row or two or more subsequent axial-direction decorative rows (R1, R2, R3, R4...) of said decorative layer including said first and second regions (30, 32) by discharging ink onto an outer surface of the tubular body over the predetermined angle in the circumferential direction of the tubular body while moving again the printer head in the generally axial direction of the tubular body throughout the prescribed portion.