A dental rotary drive cutting tool, which can limit breaking location to
the shank side, and increase life span until breakage, is provided. A
peeso reamer (10) as the dental rotary drive cutting tool according to
the present invention includes a cutting portion (11) formed on the tip
side, a shank (12) formed in a base, and a neck part (13) formed between
the cutting portion (11) and the shank (12), wherein the neck part (13)
includes a tapered portion (13a), which is wider on the tip side and
narrower on the base side, and a straight portion (13b), which has a
constant thickness with the same diameter as that of the end of the
tapered portion on the base side. While it breaks at the narrowest
portion of the tapered portion, this portion is a straight portion, and
thus increase in life span is possible.