The present invention relates to a line roller unit (25) for a fishing line guide mechanism (2) that guides a fishing line to a spool (120) of a spinning reel (100). The line roller unit (25) comprises a line roller (4), a bearing (5) positioned on an inner circumferential surface of the line roller (4), and a cylindrical member (6) that has a holding unit (60) for holding the bearing (5) and that is positioned on an inner circumferential surface of the bearing (5). The line roller unit (25) further comprises a first magnetic seal (7) that includes a first magnet (71) and a first holding member (72) that holds the first magnet (71). The first magnetic seal (7) forms a first magnetic circuit for holding a first magnetic fluid (70) positioned in a space between the cylindrical member (6) and the first holding member (72).