A selectable one-way clutch includes a first plate, a second plate, a claw, a selector plate and an outer shell. The second plate is placed on the same axis as the first plate. The second plate has a recessed portion. The claw is provided in the first plate and meshes with the recessed portion in a state where the claw projects from the first plate only when the second plate rotates in a predetermined direction. The selector plate is placed between the first plate and the second plate. The selector plate changes a state of claw. The outer shell covers an outer periphery of the first plate. The outer periphery of the first plate and an inner periphery of the outer shell have a tapered shape in which a diameter is gradually reduced toward a direction distance from the second plate.