A method for manufacturing a stretched film for producing a long-length stretched film by stretching a long-length resin film while being conveyed so as to pass through an oven in a state in which the end portions of the resin film are held by first and second grippers, wherein the oven has a preliminary heating zone, a stretching zone, a thermal fixing zone, and a reheating zone in this order from an upstream side; the stretching zone includes a specific zone having a temperature gradient capable of setting a temperature of an end portion on a second gripper side is higher than a temperature of an end portion on a first gripper side by 5° C. or higher and 15° C. or lower; and the reheating zone has a temperature capable of heating the resin film to a temperature of Tg+5° C. or higher and Tg+20° C. or lower.