To control filling balance of a resin in each cavity of an injection molding die for manufacturing multiple articles while the die is installed in a molding machine.

The injection molding die 1 comprises a side gate type molding die for manufacturing two articles, and cavities 4 and 5 of the same shape are formed between a cavity plate 2 in a fixing side and a cavity plate 3 in a movable side. A resin flow channel is branched in an opposite direction against a sprue part 6 to form a lateral runner part 7 and reaches the cavities 4 and 5 through gates 8, 8. A resin flow rate controlling die 9 for a resin, which has almost a cylindrical shape and is installed in an intermittent position of the side runner 7, can be moved under slewing, and fixed on a cavity spacer 10 on a fixing side by a fixing bolt 11. A controlling runner 9a having the same width with and communicating to the lateral runner part 7 across the center is formed on an upper surface of the resin flow rate controlling die 9. Stepped stop holes 9b are formed in a circular shape near an outer periphery, and further two holes 9d are opened in point symmetrical positions about the center.