Provided is a screw device capable of preventing occurrence of any elevation change at a joint between a ball return path of a circulation member and a loaded ball rolling groove of a nut.The circulation member 12 has end parts 14 and 15 each of which the periphery includes a rolling groove connecting part 22 positioned to the side of a loaded ball rolling groove 11a of a nut 11 and connected to the loaded ball rolling groove 11a of the nut 11 and a scooping part 23 positioned to the side of a ball rolling groove of a screw shaft 1 and scoops up balls 3 from a loaded ball rolling path. The rolling groove connecting part 22 of each of the end parts 14 and 15 is made of resin and formed integral with the nut 11.