The present invention provide an adhesive composition which is suitable for laminating a polyimide film with a copper foil in a double-sided flexible copper-clad laminate to be used for a flexible printed wiring board. The adhesive composition comprises a polyamide-imide resin, an epoxy resin, and a phosphorus-type flame retardant, wherein 15 to 40 parts by mass of the epoxy resin is compounded to 85 to 60 parts by mass of the polyamide-imide resin; a glass transition temperature of the polyamide-imide resin is 250° C. or higher; an acid value of the polyamide-imide resin is 50 to 150 mgKOH/g; the epoxy resin is liquid at 25° C.; 15 to 60 parts by mass of the phosphorus-type flame retardant is compounded to 100 parts by mass in total of the polyamide-imide resin and the epoxy resin; and 50% by mass or more of the phosphorus-type flame retardant is a phosphinic acid derivative of a phenanthrene type.