An object tracking method for an object tracking apparatus which includes a sensor for detecting one or more objects around a moving body, and a controller for tracking the detected one or more objects, the object tracking method comprising: in a case where a plurality of the objects enter a hidden area within a detection range of the sensor, estimating a positional relationship between the plurality of the objects in the hidden area; said method being characterized by determining whether the order in which the plurality of objects may come out of the hidden area can be estimated; if the order can be estimated: estimating, based on the positional relationship and before the plurality of objects come out from the hidden area, an order in which the plurality of objects may come out of the hidden area, and assigning an object that comes out of the hidden area with identification information that was already assigned to one of the plurality of the objects that entered the hidden area; and if the order cannot be estimated: assigning an object that comes out of the hidden area with new identification information that was not already assigned to one of the plurality of the objects that entered the hidden area. an object tracking apparatus which includes a sensor for detecting one or more objects around a moving body, and a controller for tracking the detected one or more objects, the object tracking method comprising: in a case where a plurality of the objects enter a hidden area within a detection range of the sensor, estimating a positional relationship between the plurality of the objects in the hidden area; said method being characterized by determining whether the order in which the plurality of objects may come out of the hidden area can be estimated; if the order can be estimated: estimating, based on the positional relationship and before the plurality of objects come out from the hidden area, an order in which the plurality of objects may come out of the hidden area, and assigning an object that comes out of the hidden area with identification information that was already assigned to one of the plurality of the objects that entered the hidden area; and if the order cannot be estimated: assigning an object that comes out of the hidden area with new identification information that was not already assigned to one of the plurality of the objects that entered the hidden area. in a case where a plurality of the objects enter a hidden area within a detection range of the sensor, estimating a positional relationship between the plurality of the objects in the hidden area; said method being characterized by determining whether the order in which the plurality of objects may come out of the hidden area can be estimated; if the order can be estimated: estimating, based on the positional relationship and before the plurality of objects come out from the hidden area, an order in which the plurality of objects may come out of the hidden area, and assigning an object that comes out of the hidden area with identification information that was already assigned to one of the plurality of the objects that entered the hidden area; and estimating, based on the positional relationship and before the plurality of objects come out from the hidden area, an order in which the plurality of objects may come out of the hidden area, and assigning an object that comes out of the hidden area with identification information that was already assigned to one of the plurality of the objects that entered the hidden area; and if the order cannot be estimated: assigning an object that comes out of the hidden area with new identification information that was not already assigned to one of the plurality of the objects that entered the hidden area.