Provided are an injection device control method, which is a control method for an injection device including a first cylinder and a second cylinder, and an injection molding system, in which an injection molding is performed with a set temperature of a heater that heats the second cylinder, a rotation speed of a screw in the second cylinder, and a cycle time as parameters. An estimated value (Q2) of energy input from the heater to a molding material and an estimated value (Q3) of energy input from the screw for shearing of the molding material are calculated, and a ratio between (Q2) and (Q3) is visualized and presented to an operator.