A treated object modifying apparatus comprising: a plasma-treating unit (10, 100, 100A, 101A, 102A, 103A, 104A, 105A, 106A, 100B, 101B, 102B, 103B, 104B, 105B, 106B, 201, 202) that comprises a first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213), a second electrode unit (14, 140, 141, 142), and a dielectric (12, 120, 121, 122) that is interposed between the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213) and the second electrode unit (14, 140, 141, 142), and that plasma-treats a treated object positioned between the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213) and the dielectric (12, 120, 121, 122) by applying a voltage to one of the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213) and the second electrode unit (14, 140, 141, 142); and a controlling unit that controls the plasma-treating unit (10, 100, 100A, 101A, 102A, 103A, 104A, 105A, 106A, 100B, 101B, 102B, 103B, 104B, 105B, 106B, 201, 202) so that an amount of plasma energy delivered to any one of sides of the treated object in a duplex treatment is smaller than an amount of plasma energy delivered to any one of the sides of the treated object in a simplex treatment, wherein the duplex treatment is a plasma treatment performed with one side of the treated object facing the first electrode unit, and another plasma treatment performed with the other side of the treated object facing the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213), and the simplex treatment is a plasma treatment performed with one side of the treated object facing the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213). a plasma-treating unit (10, 100, 100A, 101A, 102A, 103A, 104A, 105A, 106A, 100B, 101B, 102B, 103B, 104B, 105B, 106B, 201, 202) that comprises a first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213), a second electrode unit (14, 140, 141, 142), and a dielectric (12, 120, 121, 122) that is interposed between the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213) and the second electrode unit (14, 140, 141, 142), and that plasma-treats a treated object positioned between the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213) and the dielectric (12, 120, 121, 122) by applying a voltage to one of the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213) and the second electrode unit (14, 140, 141, 142); and a controlling unit that controls the plasma-treating unit (10, 100, 100A, 101A, 102A, 103A, 104A, 105A, 106A, 100B, 101B, 102B, 103B, 104B, 105B, 106B, 201, 202) so that an amount of plasma energy delivered to any one of sides of the treated object in a duplex treatment is smaller than an amount of plasma energy delivered to any one of the sides of the treated object in a simplex treatment, wherein the duplex treatment is a plasma treatment performed with one side of the treated object facing the first electrode unit, and another plasma treatment performed with the other side of the treated object facing the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213), and the simplex treatment is a plasma treatment performed with one side of the treated object facing the first electrode unit (11, 110, 111, 112, 113, 115, 210, 211, 212, 213).