A magnetic detector includes a rotor including a signal generation unit in a surface perpendicular to a rotary shaft and configured to rotate around the rotary shaft, and a detection unit configured to detect a rotational angle of the rotor by using magnetism via the signal generation unit. A plurality of concave and convex portions of the signal generation unit is formed by electroforming or sintering. In the surface, a projection portion is preferably disposed radially inside or outside the rotor with respect to the signal generation unit.