This study aims to answer whether the happiness of women having children is higher than that of women with no children using the Japanese panel data. The following four points are found as a result of the analysis for married women using life satisfaction to measure subjective well-being (SWB). First, having children is negatively associated with the life satisfaction of women. The greater the number of children, especially the larger the number of children aged 13-17, the stronger the negative impact. Second, the negative impact of children on life satisfaction does not disappear even when the household expenditure is considered. Third, the negative impact of children declines largely when marital satisfaction is considered. This result indicates that having children is likely to affect life satisfaction by decreasing marital satisfaction negatively. Fourth, the negative effect of having children disappears in the case of non-working married women when considering household expenditure and marital satisfaction. However, it remains in working married women even when considering the household expenditure and marital satisfaction.