Previous studies have suggested that being imitated by an adult is an effective intervention with children with autism and developmental delay. The purpose of this study was to investigate whether "mirroring" interaction, which includes being imitated by an adult, can facilitate the social responsiveness of toddlers with autism spectrum disorder (ASD). Participants were 16 toddlers (2- and 3-year-olds) with ASD. This study consisted of three experimental phases: in the first baseline phase, the experimenter manipulated toys in front of the participant; in the second phase, the experimenter reproduced (mirrored) all of the child's behaviors; and in the third phase, the first baseline phase was repeated. Our results demonstrated that although the mirroring effect differed by age, the effect was observed in both 2- and 3-year-olds with ASD. In addition, the overall magnitude of the mirroring effect differed by IQ, but not by the severity of autistic symptoms. Mirroring interaction is promising as an early intervention for a wide range of children with ASD. (Contains 1 figure.)