An L10-FeNi magnetic powder has an average particle size of 50 nm to 1 μm, and an average value of sphericity P of 0.9 or more. The sphericity P is defined as P=Ls/Lr, where Lr is a perimeter of an L10-FeNi magnetic powder particle on an image of a microscope, and Ls is a perimeter of a perfect circle that has a same area as the L10-FeNi magnetic powder particle on the image for which Lr is calculated.