The metal magnetic powder includes Co as a main component, and an average particle size (D50) of 1 nm to 100 nm. An X-ray diffraction chart of the metal magnetic powder has a first peak that appears in a range of a diffraction angle 2θ of 41.6±0.3°, and a second peak that appears in a range of a diffraction angle 20θ of 47.4±0.3°. When a full width at half maximum of the first peak is set as FW1, and a full width at half maximum of the second peak is set as FW2, a ratio (FW2/FW1) of FW2 to FW1 is 1 to 5.