An atomizer for atomizing a liquid by an atomizing device, the atomizing device comprising an oscillating member, a passive oscillating plate and a spray orifice, the passive oscillating plate having a plate body portion and a convex portion. The orifice sheet is coupled to the plate body portion and the convex portion to increase the bonding area and the bonding strength of the orifice plate and the passive oscillation plate, and further increase the atomization effect of atomizing the liquid by the atomizer.一種霧化器以一霧化裝置使一液體產生霧化現象,該霧化裝置含一振盪元件、一被動振盪板及一噴孔片,該被動振盪板具有一板體部及一凸部,該噴孔片結合於該板體部及該凸部,以增加該噴孔片與該被動振盪板的結合面積及結合強度,此外可增加該霧化器霧化該液體的霧化效果。