Purpose : For improvement of nursing services in ambulatory unit, ambulatory nursing activity was identified and the required time by nursing activity was measured. Method : The data were collected from 4 tertiary hospitals and 2 secondary hospitals. The method of data collection was used the self-reporting method. The 123 nurse-work days and 137 nurse-aid-work days in 6 hospitals were analyzed. Results : As a result, 11 ambulatory nursing domains and 79 ambulatory nursing activities were confirmed. Above 50% of subjects performed the general outpatient affair domain. The percentage of total time spent in each domain were as follows : general outpatient affair domain, 58.3%, patient education ${cdot}$ counseling domain, 10.8%, therapeutic care domain, 8.6% and so on. And the average hours were measured by activity and domain. Conclusion : For the improvement of ambulatory nursing care, the strategies that keep the legal standard of number of ambulatory nurse and exchange the nursing-aid for the nurse is needed. And it is also needed to standardize the ambulatory nursing services.