"ROSAI" hospital, Wakayama City in Japan, reported that inpatient's bed-downfall is one of the most serious accidents in hospital at night. Many inpatients have been having serious damages from downfall accidents from a bed. To prevent accidents, the hospital tested several sensors in a sickroom to send warning-signal of inpatient's downfall accidents to a nurse. However, it sent too much inadequate wrong warning about inpatients' sleeping situation. To send a nurse useful information, precise automatic detection for an inpatient's sleeping situation is necessary. In this paper, we focus on a clustering-algorithm which evaluates inpatient's situation from multiple angles by several kinds of sensor including night-vision CCD camera. This paper indicates new relief algorithm to improve the weakness about exceptional cases.