An emitter configured to be joined on an inner wall surface of a tube for carrying irrigation liquid at a position corresponding to a discharging port of the tube for communicating between inside and outside of the tube, and configured to quantitatively discharge the irrigation liquid in the tube out of the tube from the discharging port, the emitter being made of a resin, the emitter comprising: an intake part (143, 144, 145) configured to communicate with the inside of the tube when the emitter is joined on the tube; a first pressure reducing channel part communicated with the intake part (143, 144, 145), and configured to form a first pressure reducing channel for carrying the irrigation liquid while reducing a pressure of the irrigation liquid; a second pressure reducing channel part communicated with the first pressure reducing channel part, and configured to form a second pressure reducing channel for carrying the irrigation liquid while reducing a pressure of the irrigation liquid; a third pressure reducing channel part communicated with the first pressure reducing channel part, and configured to form a third pressure reducing channel for carrying the irrigation liquid while reducing a pressure of the irrigation liquid; a first flow rate adjusting part (131, 132, 137, 138, 160) communicated with the second pressure reducing channel part, and configured to adjust a flow rate of the irrigation liquid in accordance with a pressure of the irrigation liquid in the tube; a second flow rate adjusting part (133, 134, 139, 140, 141, 142, 170) communicated with the third pressure reducing channel part and the first flow rate adjusting part (131, 132, 137, 138, 160), and configured to adjust the flow rate of the irrigation liquid in accordance with the pressure of the irrigation liquid in the tube; and a discharging part communicated with the second flow rate adjusting part (133, 134, 139, 140, 141, 142, 170), and configured to face the discharging port when the emitter is joined on the tube, wherein the first flow rate adjusting part (131, 132, 137, 138, 160) includes a valve seat, a communication hole opening at the valve seat and communicated with the second flow rate adjusting part (133, 134, 139, 140, 141, 142, 170), and a first diaphragm part having flexibility and separated from the valve seat, the first diaphragm part being configured to be brought close to the valve seat when the pressure of the irrigation liquid in the tube is exerted on the first diaphragm part, and wherein the first diaphragm part includes a protrusion configured to be disposed at an opening of the communication hole such that a gap is formed between the protrusion and the opening of the communication hole, the protrusion having a shape with which, the closer the first diaphragm part is to the valve seat, the more deeply the protrusion is inserted to the communication hole and the wider the gap. an intake part (143, 144, 145) configured to communicate with the inside of the tube when the emitter is joined on the tube; a first pressure reducing channel part communicated with the intake part (143, 144, 145), and configured to form a first pressure reducing channel for carrying the irrigation liquid while reducing a pressure of the irrigation liquid; a second pressure reducing channel part communicated with the first pressure reducing channel part, and configured to form a second pressure reducing channel for carrying the irrigation liquid while reducing a pressure of the irrigation liquid; a third pressure reducing channel part communicated with the first pressure reducing channel part, and configured to form a third pressure reducing channel for carrying the irrigation liquid while reducing a pressure of the irrigation liquid; a first flow rate adjusting part (131, 132, 137, 138, 160) communicated with the second pressure reducing channel part, and configured to adjust a flow rate of the irrigation liquid in accordance with a pressure of the irrigation liquid in the tube; a second flow rate adjusting part (133, 134, 139, 140, 141, 142, 170) communicated with the third pressure reducing channel part and the first flow rate adjusting part (131, 132, 137, 138, 160), and configured to adjust the flow rate of the irrigation liquid in accordance with the pressure of the irrigation liquid in the tube; and a discharging part communicated with the second flow rate adjusting part (133, 134, 139, 140, 141, 142, 170), and configured to face the discharging port when the emitter is joined on the tube, wherein the first flow rate adjusting part (131, 132, 137, 138, 160) includes a valve seat, a communication hole opening at the valve seat and communicated with the second flow rate adjusting part (133, 134, 139, 140, 141, 142, 170), and a first diaphragm part having flexibility and separated from the valve seat, the first diaphragm part being configured to be brought close to the valve seat when the pressure of the irrigation liquid in the tube is exerted on the first diaphragm part, and wherein the first diaphragm part includes a protrusion configured to be disposed at an opening of the communication hole such that a gap is formed between the protrusion and the opening of the communication hole, the protrusion having a shape with which, the closer the first diaphragm part is to the valve seat, the more deeply the protrusion is inserted to the communication hole and the wider the gap.