A thermosetting fluoropolyether adhesive composition is provided. This composition cures at lower than 100° C., and the cured product exhibits good adhesion to various substrates and excellent adhesion durability at a temperature of up to 150° C. A method for adhering the composition to the substrate is also provided. The composition comprises (A) a straight chain polyfluoro compound, (B) a fluorine-containing organohydrogenpolysiloxane containing at least 2 SiH groups and not containing other functional group, (C) a platinum group metal catalyst, (D) a fluorine-containing organohydrogenpolysiloxane containing a fluorine-containing organic group, SiH group, epoxy group and/or tri(organoxy)silyl group, and an aryl group, (E) a polyhydric allyl ester compound, (F) an organosilicon compound having epoxy group and an organoxy group, and not containing SiH group, and (G) an organosilicon compound having SiH group and an aryl group, and not containing epoxy group or a tri(organoxy)silyl group, or a fluorine-containing organic group.