The invention provides a blower which can reduce noise and enhance efficiency by improving a blade structure of the blower used for, for example, an outdoor equipment of an air conditioner There is provided an impeller 1 in which plural blades 3 attached to a peripheral surface of a boss 2 at intervals in a peripheral direction are disposed, and a trailing edge of the blade 3 has a protrusion-shaped part 30 in which its central part in a radial direction is curved to expand to a suction side. By adopting such a structure, a discharge velocity of air can be made uniform along the radial direction of the blade 3 and it becomes possible to reduce noise and to enhance efficiency.