Abstract: An apparatus for precisely, speedy positioning a table on which a work piece is mounted. The apparatus has a moving mechanism in which a linear motion rolling guide unit is employed to convert the horizontal movement of a moving body by a linear motor to the vertical movement. Upon the moving body being horizontally moved with respect to the bed along first track rails through first sliding elements by mean of the linear motor, the working table moves vertically by the action of a second sliding element which moves along a second track rail on an inclined plane of the moving body. The vertical movement of the working table is controlled through third sliding elements so as to be guided along third track rails secured to a cylindrical member on the bed. The working table may make the vertical movement relative to the bed with high accuracy and high speed, irrespectively of loads variable in acting direction and magnitude.