A gear mechanism for a fishing reel includes first and second gears. The first gear has first gear teeth including a first driving side face, and a first reverse side face opposite the first driving side face. The second gear has second gear teeth including a second driven side face that meshes with a respective first driving side faces, and a second reverse side face that faces a respective first reverse side face, and opposite the second driven side faces. At least one of each of the first reverse side faces and each of the second reverse side faces includes an interference prevention portion to prevent interference with the other of the opposing first reverse side faces and second reverse side faces.
