Provided are: an emitter which is capable of inhibiting variation in the discharge amount of a liquid in a drip irrigation tube caused by the temperature of the liquid； and a drip irrigation tube. This emitter (120) is provided to an inner wall of a tube (110) provided with a discharge port (112), and adjusts the discharge of an irrigation liquid from inside the tube (110) to outside the tube (110) through the discharge port (112). The emitter (120) is provided with an intake part, an adjustment part, a discharge part, and a flow path. The adjustment part is provided with a recess and a film. The film is fixed in a state of covering an internal space of the recess. An area covering the internal space of the recess is a diaphragm part. The flow path is provided with a reduced pressure region in which the pressure of the taken in fluid is reduced. The reduced pressure region has a meandering shape. The ratio of the change in the area of cross sections of the reduced pressure region in a direction orthogonal to the axial direction is in the range of 1±0.1 relative to the area of the smallest cross section.
