Fluid supply mechanism for rotary tool

There is provided a fluid supply mechanism that, when a circular saw blade having a thick boss type base is used, can achieve lubrication and/or cooling of the circular saw blade by performing excellent mist supply. The fluid supply mechanism includes a sleeve (24) with a required length that is attached to a rotary shaft (22), a required number of doughnut-like shims (26) attached to the sleeve (24) and a rotary tool (10) which is attached to the sleeve (24) and is clamped and fixed by the shims (26) from both sides. A fluid is transferred by pressure from gutter-like passages (30) formed on an inner periphery of the sleeve (24) via through holes (32) formed in the sleeve (24) in the radial direction, the fluid is transferred by pressure to passages (34) provided on inner peripheral faces of the shims (26) and gutters (38) formed to extend in the radial direction on both sides or one side of the shims (26), and the fluid is supplied to the rotary tool (10) to lubricate and/or cool the rotary tool (10) during