Provided is a soft magnetic powder used for obtaining a dust core having a low hysteresis loss, in particular, in a high temperature range. A soft magnetic powder includes an aggregate of composite magnetic particles, each including a soft magnetic particle containing Fe, Si, and Al, and an insulating coating film disposed on the surface thereof, and satisfies the expressions (1) and (2) below: Expression (1) . . . 27≦2.5a+b≦29 and Expression (2) . . . 6≦b≦9, where a represents the Si content (mass %) and b represents the Al content (mass %). The soft magnetic powder is capable of reducing the hysteresis loss, in a high-temperature environment, of a dust core obtained using the soft magnetic powder.