To obtain a sustained release holder, useful for construction materials and food-related field, etc., having excellent medicinal sustainability without being influenced by any humidity condition, by housing an isothiocyanate in the holder provided partly with a permeable wall allowing the isothiocyanate to pass therethrough.

This holder is made up of a cup-shaped container 1 and a cover 3 and provided at least partly with a permeable portion for the isothiocyanate 2 held therein as a gel or sol substance obtained by impregnating the isothiocyanate into a polymeric material having chemical affinity for the isothiocyanate, such as polyacrylate, in such an amount that its permeating rate through the permeable portion determines the over-all permeating rate. Preferably, the wall thickness of the cup-shaped container 1 is 300 to 700μm.