according to thickness measured by the thickness measurement device 70 feed speed v and a nozzle block 11 are controlled according to the structure as mentioned above in the case of thickness of nanofiber non woven fabric discharged from a unit 10 a located in the front end of the electrospinning apparatus 1 is measured thinner than deviation the next unit 10 b feed speed can be slowed and discharging amount of nozzle block 11 is increased by adjusting voltage intensity of a voltage generator 14 a 14 b increases discharging amount of nanofiber non woven fabric per unit and makes thicker thickness also in the case of thickness of nanofiber non woven fabric discharged from a unit 10 a located in the front end of the electrospinning apparatus 1 is measured thicker than deviation the next unit 10 b feed speed v can be faster discharging amount of nozzle block 11 is lessen by adjusting voltage intensity of a voltage generator 14 a 14 b lessen discharging amount of nanofiber non woven fabric per unit lessen laminating amount and making thinner thickness and because of this nanofiber non woven fabric having uniformed thickness can be produced here the thickness measurement device 9 is arranged in up and down opposite sides put between an elongated sheet 15 which is capable of incoming and supplying and provided a thickness measurement portion comprising a.