Time use is usually analyzed from the individual aspect, not from the household aspect. Even when time use is examined from the viewpoint of the household, only husbands and wives are included in the analyses and children or parent/parents in the household are not focused on. This paper examines time devoted to unpaid work by all family members aged 10 years and over in the same household. Analyses in this paper are based on data of 2001 Survey on Time Use and Leisure Activities conducted by Statistics Bureau, Ministry of Public Management, Home Affairs, Posts and Telecommunications, Japan. Unpaid work time was analyzed by usual economic activities of married couple and family type of household. Female parents in dual-income families devoted more time to unpaid work than those in families in which only husbands did paid work. Wives living with children and parent/parents in dual-income families spent less time on unpaid work than those living with children and without parent/parents in dual-income families. Husbands and children in dual-income families did not necessarily devote more time to unpaid work than those in families in which only husbands did paid work. Interactions among family members reflected in the use of unpaid work time were cleared up.