The state of an area where one or more target objects are arranged is determined based on the result of measurement by a first sensor. A robot is controlled to grip one of the target objects by the grip unit of the robot. The gripping state of the gripping target object gripped by the grip unit is determined from the result of measuring the gripping target object by using a second sensor. When it is determined that gripping has failed, a rearrangement area where the gripping target object is to be rearranged is decided using the result of measurement by the first sensor or that of measurement by the second sensor. The robot is controlled to rearrange the gripping target object in the rearrangement area by the grip unit.