The purpose of this study is to investigate the factors that affect the second childbirth plan of working women with a preschooler. Data from 259 working women were analyzed using descriptive statistics and logistic regression analysis. Findings are as follows : First, it was found that the higher the family income, the older the age of mothers and the first child , and in the case of hiring a regular caregiver for the first child, the less working mothers tended to plan second child. Second, in the cases that the first child is a girl, that working mothers use child-care and educational services for their children, and that they are regular full-time employees, they have tendency to plan second child. Third, the higher the level of education of working mother was, the better the perception of policy to support child-rearing was, the less the difficulty in reconciliation between work and family life was and the longer the average time that both mother and father participate in child-rearing on weekdays was, the more the working mother planned to have second child. Based on these findings, this study suggest extended policy support for working mothers to plan second (and ubsequent) childbrith by (1) developing and informing of childrearing support policies, (2) providing extra support for working mothers to utilize workplace and in-home care services, and (3) improving policies to enhance employees’ parental rights for child-rearing.