Provided is a roll-to-roll surface treatment device for an elongated base material, with which treatment can be performed such that hardly any wrinkles are formed in the elongated base material and costs are suppressed. The surface treatment device comprises, within a vacuum chamber: two can rolls around the outer peripheral surface of which an elongated resin film that is conveyed roll-to-roll is wound and which cool the elongated resin film with a cooling medium that circulates inside thereof; and a surface treatment means represented by a magnetron sputtering cathode that is provided at a position opposing the outer peripheral surface of the two can rolls. Among the two can rolls, a second can roll other than a first can roll that is positioned on the most upstream side includes a gas discharge mechanism that discharges gas from the outer peripheral surface.
