The reaction-curable adhesive composition exhibiting acidity of the present invention is formed form a weakly acidic to alkaline composition (I) comprising (a) a polymerizable monomer and (b) a compound represented by the following formula (1) and a strongly acidic composition (II) comprising (a) a polymerizable monomer. €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒR 1 -C 6 H 4 -NR 2 CH 2 COOR 3 €ƒ€ƒ€ƒ€ƒ€ƒ(1) wherein R 1 and R 2 are each independently a hydrogen atom or an alkyl group which may have a functional group, and R 3 is a hydrogen atom or a metal atom. According to the present invention, a composition containing a polymerizable monomer can be stably stored for a long period of time.
