To provide an ultrasonic curable composition which can be cured with a small amount of energy even when a material such as a colorant attenuating or blocking ultrasonic waves with which the material is irradiated, is present at high concentration or when film thickness of a coating film is large.
The ultrasonic curable composition includes: (1) a radical initiator (A); (2) an acid generator (B) and/or a base generator (C); and (3) a polymerizable material (D). At least one of the radical initiator (A), the acid generator (B) and the base generator (C) generates an active species (H) upon irradiation with ultrasonic waves. The active species (H) reacts with the radical initiator (A), the acid generator (B) and/or the base generator (C) to generate a new active species (I), and polymerization reaction of the polymerizable material (D) under the new active species (I) proceeds. The active species (H) or (I) is an acid or a base.