This study investigates the determinants of the income levels of newly self-employed workers compared to those of employees, while focusing on the effects of gender and childcare. We argue that working mothers with preschool children prefer self-employment to paid employment, as such arrangements offer better work–life balance. Hence, we predict that self-employed working mothers earn lower incomes than their male counterparts, employed counterparts, and female self-employed worker counterparts who do not have preschool children. Empirical results based on anonymous micro data from Japanese employment statistics support our hypotheses.