An injection molding device includes a fixing section to which a molding die having a fixed molding die and a movable molding die, an injection section that injects a molding material, and a moving section that moves the injection section relative to the fixed molding die. The injection section includes a nozzle and an injection amount adjustment mechanism. The injection molding device further includes a control section configured to control the moving section, the injection amount adjustment mechanism, and a heater. The control section executes the following in a state where the molding die is mounted on the fixing section, a first control in which the nozzle is brought into contact with the fixed molding die and the molding material is injected, and a second control in which the nozzle is separated from the fixed molding die after a predetermined time elapses from the completion of the first control.