PURPOSE: To form a design on a slat surface without causing damage thereon by peeling design seals from mounting sheets for composing short pieces sheets, and adhering the design seals to the surfeces of slats for forming a blind to form a suitable design.

CONSTITUTION: Design sheets 3,... are peeled in the order of numbers printed on the rear faces of mounting sheets 4,... for composing a plurality of short piece sheets 8,..., and the design seals 3,... are adhered in the order of the numbers sequentially from lower or upper slats 3 of a blind 1 to the exposed front surface except the superposed parts of the slats 3,... for composing the blind 1. Thus, a design of a yacht shape made of the plurality of design seals 3,... is integrally formed on the surface of the blind 1.