A fluid control device includes a piezoelectric actuator and a deformable substrate. The piezoelectric actuator includes a piezoelectric element and a vibration plate. The piezoelectric element is attached on a first surface of the vibration plate and is subjected to deformation in response to an applied voltage. The vibration plate is subjected to a curvy vibration in response to the deformation of the piezoelectric element. A bulge is formed on a second surface of the vibration plate. The deformable substrate includes a flexible plate and a communication plate stacked on each other. A synchronously-deformed structure is defined by the flexible plate and the communication plate. The deformable substrate is bent in the direction away from the vibration plate. There is a specified depth maintained between the flexible plate and the bulge of the vibration plate. The flexible plate includes a movable part corresponding to the bulge of vibration plate.