A manufacturing method of alloy powder comprises a liquid film forming step, a supplying step and a dividing step. In the liquid film forming step, a high speed fluid made of coolant liquid is shaped into a liquid film which has a predetermined thickness of 0.1 mm or more and receives a predetermined acceleration of 2.0×104G or more along a thickness direction. In the supplying step, molten alloy which is not divided into a size of the predetermined thickness or less is supplied to the liquid film. In the dividing step, the molten alloy is divided into the size of the predetermined thickness or less by the high speed fluid to make alloy particles and keeping the alloy particles in the liquid film by the predetermined acceleration so that the alloy particles are continuously cooled in the high speed fluid.