A liquid drop ejecting head for ejecting liquid drops from nozzles communicating with liquid chambers includes a piezoelectric actuator including a diaphragm whose ends are fixed in a short-side direction of the diaphragm and an active element mounted on the diaphragm. The active element is contractible and extendable by a supply of a voltage to displace the diaphragm in an out-of-plane direction. The diaphragm is displaced with curvature so as to have a plurality of inflection points in the short-side direction. The active element is disposed in at least one area of an area from each of the ends of the diaphragm to a proximal inflection point of the inflection points and an area from one inflection point to another neighboring inflection point of the inflection points in a cross-section in the short-side direction of the diaphragm.