A valve includes a lower valve housing, a diaphragm, and an upper valve housing. A top surface of a piezoelectric pump is bonded to a bottom surface of the lower valve housing. A circular hole portion is provided in a central portion of a region of the diaphragm that opposes a projecting portion of the lower valve housing. The diaphragm is bonded to the upper valve housing and the lower valve housing, and a divided interior of a valve housing configures a first lower valve chamber, a second lower valve chamber, a first upper valve chamber, and a second upper valve chamber. A groove is located in a wall portion of the upper valve housing that opposes the diaphragm in the first upper valve chamber.
