A linear guide apparatus comprising: a guide rail having rolling element rolling grooves extending in an axial direction; and a slider having rolling element rolling grooves facing the rolling element rolling grooves of the guide rail straddling the guide rail to be capable of moving relatively in the axial direction through rolling of a large number of rolling elements inserted between the rolling element rolling grooves, wherein the linear guide apparatus comprises a side seal unit attached to an axial direction end part of the slider, wherein the side seal unit comprises a first seal member, at the slider side, arranged along the axial direction of the slider, a second seal member at an outside of the slider in the axial direction, and a lubricating member held between the first seal member and the second seal member, wherein the first seal member comprises first lip parts sliding against the rolling element rolling grooves of the guide rail, the second seal member comprises second lip parts sliding against the rolling element rolling grooves of the guide rail, the lubricating member comprises a first oil-containing member for supplying lubricant to the rolling element rolling grooves of the guide rail, wherein the first lip parts and the first oil-containing member are arranged not to come into contact with each other, and the second lip parts and the first oil-containing member are arranged not to come into contact with each other, wherein the first seal member comprises a first seal plate having the first lip parts and a first holding plate for holding the first seal plate, the second seal member comprises a second seal plate having the second lip parts and a second holding plate for holding the second seal plate, the lubricating member comprises the first oil-containing member and a case for holding the first oil-containing member, characterized in that the case is used to avoid mutual contact between the first lip parts and the first oil-containing member, and the second holding plate is used to avoid mutual contact between the second lip parts and the first oil-containing member, and wherein the first holding plate is provided with a base part formed in a substantially U-shaped cross-section and a pair of side parts which extend from both ends of the base part, respectively, and one surface of each of the pair of side parts is provided with a positioning-use projection for positioning the first holding plate at the lubricating member. wherein the linear guide apparatus comprises a side seal unit attached to an axial direction end part of the slider, wherein the side seal unit comprises a first seal member, at the slider side, arranged along the axial direction of the slider, a second seal member at an outside of the slider in the axial direction, and a lubricating member held between the first seal member and the second seal member, wherein the first seal member comprises first lip parts sliding against the rolling element rolling grooves of the guide rail, the second seal member comprises second lip parts sliding against the rolling element rolling grooves of the guide rail, the lubricating member comprises a first oil-containing member for supplying lubricant to the rolling element rolling grooves of the guide rail, wherein the first lip parts and the first oil-containing member are arranged not to come into contact with each other, and the second lip parts and the first oil-containing member are arranged not to come into contact with each other, characterized in that the case is used to avoid mutual contact between the first lip parts and the first oil-containing member, and the second holding plate is used to avoid mutual contact between the second lip parts and the first oil-containing member, and wherein the first holding plate is provided with a base part formed in a substantially U-shaped cross-section and a pair of side parts which extend from both ends of the base part, respectively, and one surface of each of the pair of side parts is provided with a positioning-use projection for positioning the first holding plate at the lubricating member.