Purpose: The relationship between the staff area and the patient's private area is the key factor in designing the structure and the environmental characteristics of ward spaces in a psychiatric hospital. Recent research has found that for the purpose of treatment and securing privacy, psychiatric patients need to be in an open space of relief rather than closed confined environment and under the watch of nursing staffs. Methods: A survey at three kinds of wards in a private psychiatric hospital in Japan was conducted in October 2002. These wards include an acute ward, a psychiatric convalescence ward, and a stress care ward. All three kinds of wards have the same structure. At each ward, spatial preferences of the 145 psychiatric inpatients were surveyed and data concerning the patient’s diagnostic category, symptoms, and activities of daily living were recorded. Results: The patients in the stress care ward prefer to stay in private spaces than public spaces. On the other hand, in the acute ward the patients seem to have a preference between managed public spaces where are monitored by nursing staffs and their private rooms where the nurse station is close. In addition, the patients in the psychiatric convalescence ward spend most of their time in the public space, such as the hallways or the day room. Implications: Base on this research, the spaces at the acute ward that could be monitored by the nursing station serves effectively as a safety space for patients was concluded. However, in the stress care ward, the patients may perceive the monitoring by the nursing staff as interruption or nuisance to their relaxation. In order to design an ideal healing environment for psychiatric patients in psychiatric ward, it is important to consider how environmental characteristics of space affect the environmental sense of patients in each ward.