Construction machine

A construction machine comprising:

• a first structure;
• a second structure relatively rotatable around a predetermined shaft relative to the first structure;
• a detection unit that is disposed on the first structure, has a predetermined detection range, and detects environment data indicating information of an environment around the first structure;
• a position information acquisition unit that acquires position information of a specific part of the second structure with respect to the detection unit from the environment data detected by the detection unit;
• a storage unit capable of storing initial position information of the specific part, the initial position information being acquired from the environment data by the position information acquisition unit at initial setting when the second structure is disposed at an initial posture around the shaft, the initial posture being previously set so that the second structure is included in the detection range of the detection unit and outputting the initial position information;
• and
• a displacement detection unit that compares comparative position information of the specific part, the comparative position information being acquired from the environment data by the position information acquisition unit, with the initial position information output from the storage unit to detect a displacement of the detection unit in the first structure when the second structure is brought into the initial posture again after the initial setting.