Provided is a rolling-element screw device in which a recess can be easily formed in an outer diameter portion of a nut main body for receiving a circulation member. At both ends of a straight passage 5 of the nut main body 2, a pair of circulation members 8 is provided respectively, in each of which a direction change passage 6 is formed for connecting the straight passage 5 to a loaded rolling-element rolling passage 3. The circulation members 8 in a pair are fit in a pair of recesses 15, respectively, formed in the outer diameter portion of the nut main body 2. The direction change passage 6 of each circulation member 8 has a curve passage 22 which is connected to the loaded rolling-element rolling passage 3. The curve passage 22 is formed in such a way that, when seen in the axial direction of the nut main body 2, the track of the center of each rolling element 7 moving in the curve passage takes the shape of an arc.