Abstract: An antimicrobial adhesive sheet containing an antimicrobial agent which exerts the antimicrobial activity not only on an attached site but also in the space in the vicinity of the attached site, and an antimicrobial method using the sheet. The antimicrobial adhesive sheet has a moisture permeability of at least 1,000 g/m2·24 hrs as the whole sheet, where a non-aqueous adhesive layer containing a vaporizable antimicrobial agent is formed on one side of the support. As the support, non-woven fabric and porous plastic sheet are preferable. In case of non-porous plastic sheet, polyurethane resins and polyamide resins are preferably used. As the vaporizable antimicrobial agent, hinokitiol is preferable and inclusion compounds thereof may also be used. As the adhesive, an acrylic adhesive prepared by polymerizing a (meth)acrylic acid alkyl ester as the main component is preferably used.