Stage mechanism

A stage mechanism comprising:

• a feed screw;
• a fixed stage having a space portion incorporating the feed screw;
• a movable stage performing a predetermined movement in response to a rotational motion of the feed screw;
• a backlash absorbing portion preventing backlash of the feed screw;
• a deviation preventing portion provided near a first end portion as one end of the feed screw, in contact with a wall of the space portion, and preventing the feed screw from deviating in a direction toward the first end portion;
• and
• a pressing force adjusting portion having an end in contact with a second end portion as the other end of the feed screw and adjusting a pressing force by which the feed screw is pressed in a direction from the second end portion side to the first end portion, the other end of the pressing force adjusting portion being fixed to the wall of the space portion, wherein
• the pressing force adjusting portion includes a spherical member and a spherical surface pressing member having a recess at a tip, the recess has a shape in contact with a surface tangent to the spherical member, the second end portion includes a spherical surface pressure receiving portion having a recess at a tip, the recess has a surface in contact with a surface tangent to the spherical member, and the spherical member is sandwiched by the spherical surface pressure receiving portion and the spherical surface pressing member on an axis of the feed screw.