connected to the lower ball rolling passage 6a upper ball rolling passage 6b and to the ball return passage hole 7a 7b of the slider main body 2a without causing stepped portions at the joining portions an infinitely circulating route is formed by the lower ball rolling passage 6a the curved passage 9a and the ball return passage hole 7a and another infinitely circulating route is formed by the upper ball rolling passage 6b the curved passage 9b and the ball return passage hole 7b the balls b are inserted as rolling members in the infinitely circulating routes as shown in fig2 furthermore with reference to fig2 through holes 30 of the bolts b1 are formed in the guide rail 1 to secure the guide rail 1 of the linear guide apparatus l to the base b and screw holes 31 are formed in the slider 2 to secure the table t to the slider 2 a side seal 32 is fixed to the end cap 8 to wipe the ball rolling grooves 3a and 3b of the guide rail 1 to prevent the intrusion of foreign matters with reference to fig1 an under seal 33 is accommodated in a recess 34 at a lower end of the side wall 4 of the slider main body 2a and the under seal 33 is held with its opposite ends fitted into under seal attaching recesses 35 fig4 of the.