To provide a fluid jetting device capable of simplifying a disassembly/ assembly structure for a jetting system unit and improving operability, in the fluid jetting device allowing the jetting system unit sucking and discharging a jetting fluid to be attached and detached so as to facilitate the replacement of a liquid contact part of the fluid jetting device.

The jetting system unit is detachably attached to the fluid jetting device provided with a pressure converting part for pressurizing the jetting fluid and used for actually sucking and discharging the jetting fluid. A bag-like elastic member provided with an upper opening part is composed attachable to and detachable from a connecting-sealing member provided with a suction valve and a discharge valve and locked to the opening part, a sealing member for sealing the mounting part of the elastic member is allowed to be reciprocatively slidable in the axial direction, and the mounting part is structured so as to be brought into a sealed state and into an opened state.