A molding mold and a molding method are disclosed, for molding a flange configuration in which a flange of a reel hub portion can be maintained in a predetermined configuration. Also a tape cartridge is disclosed, which can securely prevent a tape-shaped recording medium from touching at the flange while the tape cartridge is being used. In the molding mold for molding, a flange configuration is produced, which is provided with a reel hub portion having a flange and a hub arranged at a substantially center of the flange and an insert portion disposed at a substantially center of the reel hub portion at an opposite side of the hub, and which includes: an insert attaching portion; a flange forming portion for forming the flange; and a hub forming portion for forming the hub; wherein in a forming surface of at a side of the hub forming portion of the flange forming portion, a dimension of a circular area over from a root end of the hub forming portion to a substantially intermediate portion between the root end and a circumferential end of the flange forming portion, is corrected in view of deformation upon molding.