The present invention provides an information processing device that sets a range designated within a captured image (3) as a range of a bed reference plane. During this setting, the information processing device evaluates whether the designated range is suitable as the range of the bed reference plane, based on a predetermined evaluation condition, and presents the result of that evaluation to a user. It is thereby possible to easily perform setting relating to a position of the bed that serves as a reference for detecting the behavior of a person being watched over.
