We created a new educational material focused on three benefits of a morning-typed lifestyle and actual strategies for promoting this lifestyle. The material is a leaflet entitled, “Three benefits from going to bed early, getting up early and having breakfast. Message to mothers and fathers of young children!” In the present study, we attempted to evaluate the educational efficacy of a month-long intervention using this leaflet on 2- to 6-year-old Japanese children. About 1200 children and their parents were asked to participate in a month-long intervention from mid-June, 2011. Just before and three months after the intervention period, an anonymous integrated questionnaire was administered to participants. Responses were received from 61% of pairs (children: 363 girls and 375 boys; parents: 689 mothers and 56 fathers). Children tended to be more morning-typed after the intervention than before the intervention (p=0.07), but there was no significant difference in the Diurnal Type Scale (DTS) scores of their parents. The body mass index (BMI) of the children was significantly lower three months after the intervention period than just before the intervention (p=0.04). In the children, implementation scores were significantly correlated with their post-intervention DTS scores (p=0.001), but not with post-intervention BMI. The intervention program particularly increased morning-typed lifestyles in children through the limitation of TV and video games.