To provide a linear motion bearing which is easily manufactured and movable by a comparatively small driving force in the lengthwise direction in a state of rotation of a shaft body in the circumferential direction being suppressed.

This linear motion bearing includes a cylindrical body (11) whose inner edge of a cross section perpendicular with respect to the lengthwise direction is circular, a cylindrical holder (12) rotatably holding a plurality of rolling elements disposed along the inner peripheral face of the cylindrical body (11) in a state of each rolling element partially projected toward each of an inner peripheral side and an outer peripheral side, and a cylindrical shaft body (13) stored in the cylindrical holder (12) in a state of being supported by each of the rolling elements. At least one groove (13a) extending along the lengthwise direction is formed in the outer peripheral face of the shaft body (13). The plurality of rolling elements comprise a plurality of spherical rolling elements (18) each disposed between each of the inner peripheral face of cylindrical body (11) and the outer peripheral face of the shaft body (13) and in contact with both faces, and a plurality of cylindrical rolling elements (19) each disposed between the inner peripheral face of the cylindrical body (11) and the inner face of the groove (13a) and in contact with both faces.