To provide a more inexpensive production method where the securance of oil sealability as an oil sealing crawler, the securance of its excellent toughness to an impact, severe load and the improvement of its wear resistance and wear life are attained.

By a means where, after a crawler bush 5 whose whole body has been heated is preferentially cooled from either the outer circumferential face or inner circumferential face thereof, the whole circumferential face is cooled, or a means where high frequency heating is performed from the opposite face thereof during the preferential cooling; an outer circumferential hardened layer 2, an edge quench hardened layer 4 and an inner circumferential tempered martensite hardened layer 6 are formed. Also, a soft layer 1 formed between the outer circumferential hardened layer 2 and the inner circumferential tempered martensite hardened layer 6 is composed of one or more kinds selected from a pearlite structure, a bainite structure, a martensite structure and a martensite structure, and the soft layer is connected to the inner circumferential face of the edge face part.

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