The endoscope accessory case 61 has a case main body 62 having an opening 62 d on its top surface and having a fluid introduction port 62 i for introducing a fluid and comprising a bottom portion 62 c and a water impermeable barrel portion 620, 62 which is in contact with the inner circumference of the case main body 62 and which is brought into contact with the inner circumference of the case main body 62 and has a bubble leading edge 63 b for leading out air bubbles and which removably covers the opening 62 d,内視鏡付属品ケース61は、天面に開口部62dを有し、流体を導入する流体導入口62iを有し、底部62cおよび遮水可能な胴部620からなるケース本体62と、ケース本体62と接触する接触部63aおよびケース本体62の内周と離間した位置にあって気泡を導出するための気泡導出縁63bを有し、着脱可能に開口部62dを覆い、遮水可能な蓋63と、を含む。
