An apparatus for monitoring an object in a video received from at least one camera, comprises a storage unit storing a plurality of pieces of rule information each defining a condition of an object and a movement of the object to be observed in the condition, an input unit inputting information for identifying a monitored object and information representing a condition of the object, an acquiring unit acquiring rule information defining a movement to be observed for the object by referring to the storage unit based on the information representing the condition of the object, which is input by the input unit; and a monitoring unit determining whether the object in the video exhibits the movement to be observed, which is represented by the rule information acquired by the acquiring unit, and output a result of the determination.