Abstract: It is an objective of the present invention to provide an injection molding machine capable of preventing a molding defect and a method of controlling the injection molding machine. An injection molding machine according to the present embodiment is an injection molding machine that molds a product for each execution of a molding cycle through an injecting process of injecting a material into clamped molds, a dwell process of controlling dwell pressure of the material in the molds, and a cooling process of cooling the material in the molds, the injection molding machine including a mold opening amount sensor and a controlling unit, the mold opening amount sensor being configured to detect a mold opening amount of the molds, the controlling unit being configured to control clamping force of the molds and the dwell pressure based on the mold opening amount during the molding cycle.