INSERT MOLDED ARTICLE, MANUFACTURING METHOD FOR PROTECTIVE COVER HAVING SENSOR HOLDER PART, AND MANUFACTURING METHOD FOR BEARING DEVICE INCLUDING THE PROTECTIVE COVER

There is provided a manufacturing method for a protective cover having a sensor holder part that maintains high reliability over the long term by increasing fixing strength between a cup-shaped main part and a synthetic resin through insert molding. A cup-shaped main part 1A is positioned at one axial end of a bearing, press-fitted into an outer ring, and has a through hole 6A in a bottom 6. The manufacturing method includes: a press working step of forming the cup-shaped main part 1A by press working; and an injection molding step of performing injection molding with a nut 10 and the cup-shaped main part 1A as insert articles for attachment of a magnetic sensor A to form a wrap-around portion 8B extending radially outward on an inner side of the bottom 6 through the through hole 6A at a sensor holder part 8 integrated with the nut 10 and the cup-shaped main part 1A.