PURPOSE: To surely scrape the adhering soil on a cutter during excavation, by installing an adhering soil scraping member made of flexible material, on a guide body, on the part ranging from the projection end of the cutter to the surface side of a drum.

CONSTITUTION: A flexible scraping member 30 is installed on a holding body 20 in a discharge conduit 8 for discharging the excavated soil. As the scraping member 30, is used a steel twisted wire. In this case, the top edge of each scraping member 30 is extended to the peripheral surface of a drum 2. More preferably, a gap in 1-50mm or so is formed between the drum 2, and a nearly close contact state is generated. Further, a cutter 3 is arranged so as to make contact with one among a plurality of scraping members 30. Excavation is carried out by revolving the drum 2 and the cutter 3. In this case, the adhering soil on the peripheral surface of the drum 2 and the periphery of the cutter 3 is scraped out by the scraping member 30.