An injection mold for molding an insert element which includes a material belt with two belt holes formed therein and a plurality of terminals. Each terminal has a fastening portion with an inserting hole formed therein and a contact portion. The injection mold includes a male mold, a plurality of locating elements, a fastening element, a plurality of locating pieces and a female mold. The male mold has a cavity and a plurality of inserting grooves. Each locating element mounted to the male mold has a locating head extending beyond the male mold for inserting into the belt holes. The fastening element mounted to the cavity has a plurality of fastening grooves for respectively receiving the fastening portions. Each locating piece inserted into the inserting grooves has an inserting portion passing through the inserting hole and supporting the contact portion. The female mold is engaged with the male mold.