To provide a magnetic powder production method, a magnetic sheet production method, and an antenna module production method that are capable of reducing a size of magnetic particles, achieving thinning and a low loss, and improving magnetic permeability without lowering it.At least two oxide-based magnetic materials are mixed, preliminarily calcined, and pulverized. The pulverized magnetic materials are typically formed into a paste by being dispersed in an organic solvent, and the magnetic materials are applied onto a film after being subjected to defoaming processing. Accordingly, a sheet-like magnetic material is formed. The sheet-like magnetic material is cut into predetermined sizes so as to be fragmented into particles, with the result that magnetic particles are formed.