The main purpose of the long-term care insurance system established in 2000 in Japan was the socialization of care. In other words, it was aimed at shifting the care that has been informally provided by family members, etc. to the formal public care services. Several previous studies have investigated the extent of the socialization of care that has been achieved (Tamiya et al. 2011; Sugawara and Nakamura 2014). These studies examine how the use of formal public care services affects informal care and labor market outcomes. In addition to these perspectives, it is also important to examine how the informal care situation affects various outcomes including the labor market, because public care services do not completely substitute informal care. In this paper, we focus on the following two points. First, we show who provides informal care to whom since the foundation of the long-term care insurance system in Japan. Second, we quantitatively clarify how informal care is affecting various outcomes such as labor market participation, employment status, and wages.