Magnetic encoder and manufacturing method thereof

A manufacturing method of an axial-type magnetic encoder, comprising:

• a press molding step of fabricating by press molding an annular fixing member that has a cylindrical part attached to a rotating body and an inward flange part extended more radially inward than an end edge of the cylindrical part;
• and
• an injection molding step of, while the annular fixing member is placed in an axial draw mold, injecting a dissolved annular plastic magnet material into the mold, wherein
• the manufacturing method includes a step of, while the annular fixing member is composed of a cylindrical part and an inward flange part extended radially inward from an end edge of the cylindrical part, forming by a press process a high-form accuracy surface on a sensor-opposed surface more radially outward than a range of a diameter (d−2·r) determined by an inner diameter (d) of the cylindrical part and a radius (r) of a corner between the cylindrical part and the inward flange part, and
• the injection molding step is performed in the state where the annular fixing member is placed in the mold such that a mold matching surface is positioned on the high-accuracy surface.