1. An object state identification method of identifying an object state including at least one of a position and a posture of an object with respect to a sensor by obtaining actual measured values at a plurality of points on a flat portion of the object by the sensor, the actual measured values being three-dimensional data, the flat portion being on a surface of the object and including an opening, the object state identification method comprising: generating a model value group that is a set of model values indicating positions of a plurality of points present on at least three different surfaces of a three-dimensional corner model; calculating a model feature value based on at least one model value included in the model value group; calculating an actual feature value based on each of the actual measured values by a method that is same as a method used to calculate the model feature value; extracting a corresponding point value indicating a position of an edge of the opening based on the actual feature value that matches the model feature value; identifying the object state of the object based on the corresponding point value; and controlling a carrier for carrying the object based on the object state of the object.