A spinning reel comprising: a reel body , a driving member rotatably supported on the reel body and including a pinion gear , the pinion gear being configured to be rotated by an operation of a handle of the spinning reel ; a housing part that is fixed to the reel body and that includes an opening part, the housing part at least partially accommodating the driving member extending through a central opening of the opening part, a one-way clutch being located between the pinion gear and the housing part in the reel body ; and a magnetic seal device being mounted to the opening part of the housing part , wherein the magnetic seal device seals a gap between the housing part and the pinion gear of the driving member at the opening part of the housing part ; wherein the magnetic seal device comprises: a magnetic body being fitted to the pinion gear ; a ring-shaped magnet being located radially outside of the magnetic body ; a first magnetic plate and a second magnetic plate both having a ring shape and being disposed on axially opposite sides of the magnet , the first magnetic plate and the second magnetic plate being fixed to the housing part ; and a magnetic fluid being disposed at a gap between the magnetic body and the first and second magnetic plates , the magnetic fluid being maintained at the gap by magnetic force, wherein the first magnetic plate is provided closer to the one-way clutch compared with the second magnetic plate , said spinning reel being characterized in that the first magnetic plate has a larger outer diameter than the second magnetic plate . a reel body , a driving member rotatably supported on the reel body and including a pinion gear , the pinion gear being configured to be rotated by an operation of a handle of the spinning reel ; a housing part that is fixed to the reel body and that includes an opening part, the housing part at least partially accommodating the driving member extending through a central opening of the opening part, a one-way clutch being located between the pinion gear and the housing part in the reel body ; and a magnetic seal device being mounted to the opening part of the housing part , wherein the magnetic seal device seals a gap between the housing part and the pinion gear of the driving member at the opening part of the housing part ; wherein the magnetic seal device comprises: a magnetic body being fitted to the pinion gear ; a ring-shaped magnet being located radially outside of the magnetic body ; a first magnetic plate and a second magnetic plate both having a ring shape and being disposed on axially opposite sides of the magnet , the first magnetic plate and the second magnetic plate being fixed to the housing part ; and a magnetic fluid being disposed at a gap between the magnetic body and the first and second magnetic plates , the magnetic fluid being maintained at the gap by magnetic force, a magnetic body being fitted to the pinion gear ; a ring-shaped magnet being located radially outside of the magnetic body ; a first magnetic plate and a second magnetic plate both having a ring shape and being disposed on axially opposite sides of the magnet , the first magnetic plate and the second magnetic plate being fixed to the housing part ; and a magnetic fluid being disposed at a gap between the magnetic body and the first and second magnetic plates , the magnetic fluid being maintained at the gap by magnetic force, wherein the first magnetic plate is provided closer to the one-way clutch compared with the second magnetic plate , said spinning reel being characterized in that the first magnetic plate has a larger outer diameter than the second magnetic plate . <EOS>