To make it possible to apply decoration to a bag by utilizing a design forming method with the same high degree of freedom as that in a flower arrangement by inventing a method for freely engaging and disengaging a plurality of accessories, which have preserved flowers as accessory material with and from the portion to be decorated of the bag, and at the same time, apply a designed decoration with a high degree of freedom to utility products by freely engaging and disengaging accessories, the material of which is not limited to the preserved flowers, with and from a body to be decorated not limiting to the bag by applying the method.

A plurality of the accessories 10, each of which is formed by joining a securing member 11 with a recessed part to the accessory material 12 such as the preserved flowers or the like, are manufactured so as to be detachably secured to each of members 21 to be secured having a projected part fixed to the portion 20a to be decorated of the body 20 to be decorated for decoration.