PURPOSE: To facilitate manufacture and handling and enable mass production by interconnecting adjacent elastic bodies in the thin portions to mold them in a body.

CONSTITUTION: An elastic body 7 is formed between adjacent crawler unit parts 1A with the thin portion 23. The elastic body 7 around a shoe plate 2 and the elastic body 7 in the thin portion 23 are molded in a body to connect the crawler unit parts 1A through the thin portion 23. A metal mold consists of a fixed metal mold 11A and vertically movable split metal molds 11B, 11C to form a material reducing part 12A for forming a defining line of respective crawler units 12A. The material reducing part 12A is the parts of the split metal molds 11B, 11C projecting to the fixed metal mold 11A side to form thereby the thin portion 23. The thin portion 23 acts to join a plurality of crawler unit parts 1A in manufacture and transportation.