A method of producing a functional roll comprising a rotation shaft and a roll body comprising nonwoven fabric sheets provided on the rotation shaft, including the following steps: stacking multiple nonwoven fabric sheets shaped into a circular form with an opening in the center while a mounting shaft is inserted in the opening; clamping a first nonwoven fabric sheet group comprising the multiple stacked nonwoven fabric sheets with a set of a first jig and a second jig, and compressing the first nonwoven fabric sheet group in the direction parallel to the mounting shaft via the jigs (16, 17); securing the set of jigs (16, 17) to each other to unite the nonwoven fabric sheets forming the first nonwoven fabric sheet group; stacking multiple nonwoven fabric sheets other than the nonwoven fabric sheets forming the first nonwoven fabric sheet group while the mounting shaft running through the first nonwoven fabric sheet group united with the first and second jigs (16, 17) is inserted; clamping a second nonwoven fabric sheet group comprising the multiple newly stacked nonwoven fabric sheets with a set of the second jig and a third jig, and compressing the second nonwoven fabric sheet group in the direction parallel to the mounting shaft via the jigs (16,17); heating the first united nonwoven fabric sheet group and the second united nonwoven fabric sheet group so that the nonwoven fabric sheets forming the first nonwoven fabric sheet group adhere to each other and the nonwoven fabric sheets forming the second nonwoven fabric sheet group adhere to each other; and removing the mounting shaft and jigs (16, 17) from the nonwoven fabric sheets adhering to each other to create multiple modules comprising the nonwoven fabric sheets adhering to each other. stacking multiple nonwoven fabric sheets shaped into a circular form with an opening in the center while a mounting shaft is inserted in the opening; clamping a first nonwoven fabric sheet group comprising the multiple stacked nonwoven fabric sheets with a set of a first jig and a second jig, and compressing the first nonwoven fabric sheet group in the direction parallel to the mounting shaft via the jigs (16, 17); securing the set of jigs (16, 17) to each other to unite the nonwoven fabric sheets forming the first nonwoven fabric sheet group; stacking multiple nonwoven fabric sheets other than the nonwoven fabric sheets forming the first nonwoven fabric sheet group while the mounting shaft running through the first nonwoven fabric sheet group united with the first and second jigs (16, 17) is inserted; clamping a second nonwoven fabric sheet group comprising the multiple newly stacked nonwoven fabric sheets with a set of the second jig and a third jig, and compressing the second nonwoven fabric sheet group in the direction parallel to the mounting shaft via the jigs (16,17); heating the first united nonwoven fabric sheet group and the second united nonwoven fabric sheet group so that the nonwoven fabric sheets forming the first nonwoven fabric sheet group adhere to each other and the nonwoven fabric sheets forming the second nonwoven fabric sheet group adhere to each other; and removing the mounting shaft and jigs (16, 17) from the nonwoven fabric sheets adhering to each other to create multiple modules comprising the nonwoven fabric sheets adhering to each other.