This study examines how the problem of child abuse has been constructed in Japan. It reveals that a recent outflow of 'discourse' regarding child abuse has changed the major image of the problem from 'poverty related' to 'medical related'. Such medicalization of the problem helps to gain the credibility of statement that child abuse occurs among families from all socioeconomic levels and is increasing due to dysfunction of family. While such an oft-repeated statement might be true, it is also true that the concept of child abuse has broadened to include the marginal cases which were not regarded as problems before.<br> Construction of child abuse as a family problem questioning the prominency in family's child rearing function relates to a recent change in the child protection scheme which has begun to focus our attention on 'system' rather than on family-school exclusive unit. The study lastly discusses discourse itself from Michel Foucault's perspective; namely the relationship among discourse, subject and power.