The invention discloses a cantilever working mechanism comprising a cutting head (1) and an expansion part (2), wherein the cutting head (1) is covered on the front end part of the expansion part (2); a spiral chip removal part (3) is arranged between the cutting head (1) and the expansion part (2); the spiral chip removal part (3) is connected to the cutting head (1); a gap (4) is formed betweenthe chip removal part (3) and the expansion part (2); the spiral chip removal part (3) is cylindrical; and the inner wall surface of the spiral chip removal part (3) is provided with a spiral groove (31) of which the screwing-in direction is coincident with the rotation direction of the cutting head (1). The cantilever working mechanism with the structure has the advantages of strong chip removalfunction and better tightness. The invention also discloses a heading machine comprising a cantilever supporting mechanism and the cantilever working mechanism, wherein the cantilever working mechanism is supported on the cantilever supporting mechanism. The heading machine has the same technical effect with the cantilever working mechanism.