A working machine pad (16) support structure provided in a working machine support belt (1) includes a front support band (14) that supports a front portion (16f) of the working machine pad (16), and a rear support band (13) that supports a rear portion (16r) of the working machine pad (16). The front support band (14) is provided with a second length adjustment mechanism (21), and the rear support band (13) is provided with a third length adjustment mechanism (25).