Provided is a medical instrument guide device capable of obtaining an image desired by an operator with a simple configuration. The mantle tube 100 punctured into the body wall includes an endoscope insertion hole 120 through which the endoscope 10 is inserted and a treatment tool insertion hole 122 through which the treatment instrument 50 is inserted. Inside the mantle tube 100, an interlocking mechanism 134 for advancing and retracting the endoscope 10 in conjunction with advancing and retreating movement of the treatment instrument 50 is provided. The interlocking mechanism 134 includes an endoscope side roller 200 which is in contact with the endoscope insertion section 12 and interlocked with the endoscope insertion section 12, and a treatment tool side roller 202 which is in contact with the treatment tool insertion section 52 and moves in conjunction therewith, and these rollers 200, 202 Are rotated in conjunction with each other. As a result, the treatment instrument side roller 202 and the endoscope side roller 200 rotate in opposite directions against the forward and backward movement of the treatment tool insertion section 52, and the endoscope insertion section 12 moves forward and backward. In the treatment instrument insertion section 52, a play is provided in which the endoscope 10 does not interlock with the movement of the treatment instrument 50.術者が望む画像を簡単な構成により得ることができる医療器具案内装置を提供する。体壁に穿刺される外套管100は、内視鏡10を挿通する内視鏡挿通孔120と、処置具50を挿通する処置具挿通孔122を備える。外套管100の内部には処置具50の進退移動に対して、内視鏡10を連動させて進退移動させる連動機構134を備える。連動機構134は内視鏡挿入部12と接触して連動する内視鏡側ローラ200と、処置具挿入部52と接触して連動する処置具側ローラ202とを備え、それらのローラ200、202は連動して回転する。これにより、処置具挿入部52の進退移動に対して処置具側ローラ202及び内視鏡側ローラ200が反対方向に回転し、内視鏡挿入部12が進退移動する。また、処置具挿入部52には、処置具50の移動に内視鏡10が連動しない遊びが設けられる。