Ball screw device

A ball screw device comprising:

• a screw shaft that has a first helical groove on an outer circumference thereof;
• a nut disposed on an outer circumferential side of the screw shaft and having a second helical groove on an inner circumference thereof;
• a plurality of balls disposed between the first helical groove and the second helical groove;
• a stopper disposed at an end portion of the second helical groove;
• and
• a spring body disposed between the stopper and an end portion ball closest to the stopper out of the plurality of balls, the spring body including:
• a first coil spring arrayed along the first helical groove and the second helical groove, the first coil spring having:
• a first spring middle portion;
• and
• a first spring end portion having a higher rigidity than a rigidity of the first spring middle portion;
• and
• a second coil spring arrayed along the first helical groove and the second helical groove, the second coil spring being adjacent to the first coil spring, the second coil spring having:
• a second spring middle portion;
• and
• a second spring end portion having a higher rigidity than a rigidity of the second spring middle portion, the second spring end portion being in contact with the first spring end portion.