PROBLEM TO BE SOLVED: To provide a fluid injection device capable of securing a visual field of the affected area, and a medical instrument.SOLUTION: The fluid injection device includes: a pulsation generation section 14 which comprises a fluid chamber 30 capable of changing a capacity, inlet and outlet channels 30A and 30B communicating with the fluid chamber 30, and a capacity changing portion 42 changing the capacity of the fluid chamber 30 depending on supply of a drive signal a fluid injection pipe 16 which emits a jet of fluid from a fluid injection opening 28 communicating with an end different from an end, communicating with the fluid chamber 30, of the outlet channel 30B and a gas injection pipe 18 which is disposed on the outer periphery of the fluid injection pipe 16, which forms a gas injection channel 34 between itself and an outer peripheral surface of the fluid injection pipe 16, and which emits a jet of gas from a gas injection opening 36 communicating with an end of the gas injection channel 34. The inside diameter of the fluid injection pipe 16 in the fluid injection opening 28 is larger than that of the fluid injection pipe 16 in a position nearer to the fluid chamber 30 than to the fluid injection opening 28.COPYRIGHT: (C)2012,JPO&INPIT【課題】患部視野を確保することができる流体噴射装置及び医療機器を提供する。【解決手段】流体噴射装置は、容積が変更可能な流体室30と、流体室30に連通する入口流路30A及び出口流路30Bと、駆動信号の供給に応じて流体室30の容積を変更する容積変更部42と、を備える脈動発生部14と、出口流路30Bの流体室30に連通する端部とは異なる端部に連通する流体噴射開口部28から流体を噴射する流体噴射管16と、流体噴射管16の外周に配設され、流体噴射管16の外周面との間に気体噴射流路34を形成し、気体噴射流路34の端部に連通する気体噴射開口部36から気体を噴射する気体噴射管18と、を有し、流体噴射開口部28における流体噴射管16の内径は、流体噴射開口部28よりも流体室30に近い位置における流体噴射管16の内径よりも大きい。【選択図】図1
