To suppress a pressure pulsation in at least one pipe of the pipes connected to a fluid upstream side and downstream side, and an operation sound audible outside, in a fluid injection device.

A hydrogen gas injection device 50 includes: a flow control valve 58 which is installed inside a case 56; accumulator chambers 60 and 62 which are inside the case 56 and installed on the upstream side and the downstream side, respectively, of the flow control valve 58 in relation to a gas flow direction; a bracket 64 which is installed outside the case 56 and is attachable to a fixed part; and a rubber mount 66 which is installed between the bracket 64 and the case 56.