In Japan, mothers’ child-rearing anxiety is a serious concern; mothers’ anxieties appear to arise from family situations in which mothers do not expect to receive sufficient support for child-rearing from their spouses, because their working hours are very long. In contrast, in the Netherlands, equal sharing by men and women of time between paid and unpaid work has been promoted by emphasizing ... [Show full abstract] work-life balance in society. The present study examined how work-life balance affects co-parenting of young children in these two countries, by having parents of pre-schoolers complete questionnaires. Completed questionnaires from Japanese parents (92 mothers, 176 fathers) and Dutch parents (85 mothers, 79 fathers) were analyzed. The findings suggested that, in both countries, mothers spent more time taking care of their children than fathers did. However, the difference between mothers and fathers was significantly larger among Japanese parents, compared to Dutch parents. No difference was found between mothers and fathers, or between Japan and the Netherlands, in positive feelings toward childrearing. Moreover, whereas, in Japan, negative feelings toward childrearing were significantly higher among mothers compared to fathers, no such difference was found among Dutch parents.