This emitter (120) has double ridges provided around a hole (173) which forms a portion of a flow path between a reduced-pressure flow path and a discharge part. A first ridge (174), which is the outermost ridge, is provided with four first grooves (177) which intersect said ridge. A second ridge (175) is provided with one second groove (178) which intersects said ridge. As the external liquid pressure increases, a film (140) sequentially adheres to the first ridge (174) and the second ridge (175). The flow rate of an irrigation liquid is adjusted to an amount capable of passing through the groove or grooves in the ridge to which the film (140) is adhered.
