To provide a rotary saw with reduced noise during cutting and a cleaner (deuse) cutting face.

In this rotary saw comprising a multiplicity of teeth 13 protruding outward in a radial direction provided on an outer circumference of a disclike base metal 11, a first slit 15 formed on an outer circumference part of the base metal 11 and where an outer circumference end thereof opens to a recessed part 14 between predetermined teeth 13, and a second slit 16 formed on an intermediate circumference part of the base metal 11 while maintaining a predetermined interval with the first slit 15, an outer circumference part 16a of the second slit 16 of a length within a range of 4 mm to 30 mm is provided along an inner circumference part 15b of the first slit 15, an interval W of the inner circumference part 15b and the outer circumference part 16a is within a range of 1.5 mm to 4 mm, and a viscous material having viscosity under ordinary temperature is filled in at least one slit of the first and second slits 15 and 16.