We surveyed the state of nurse working environment and job satisfaction and used data mining to clarify the factors that influence nurses to leave the nursing profession; this was done to find ways to prevent nurses from leaving their jobs. With the perspective of bed management added as a working environment factor, the questionnaire was administered during March 2011 to 4,803nurses from 25 social insurance hospitals throughout Japan, who consented to cooperate.Responses were obtained from 4,087 nurses and the 2,112 nurses with no missing values for responses were included in subject analysis. Data mining was based on a characteristic discriminant model of decisions to leave the nursing profession. Nurses “not wanting to quit their job” were influenced by working environment and manager expectation and approval. Nurses “considering quitting their job” were influenced by interpersonal relationships with superiors, degree of autonomy in decision-making, and educational support. Bed management also influenced “considering quitting their job.” We found that the role of the head nurse is important in preventing nurses from quitting their jobs and that management, including bed control, is needed.