A fluid control device 1 includes a casing 10 configured to house a cylindrical infusion tube 100 and a droplet detecting section 60 configured to detect the amount of droplets dripping from a nozzle 124 in the infusion tube 100 housed in the casing 10. The infusion tube 100 includes a flange protruding outward. The casing 10 includes an engagement member 30. The engagement member 30 includes a flange configured to engage with the flange in the infusion tube 100 in a direction along the longitudinal direction of the infusion tube 100 and fix the infusion tube and a fixation surface configured to fix the infusion tube 100 in a direction orthogonal to the longitudinal direction of the infusion tube 100.