To combine miniaturization and simplification of structure while preventing a fault of a holding means.

A cylinder lock 10 includes: a switching tumbler hole 12c; a switching tumbler 14 arranged in the switching tumbler hole and constituted to be movable in a direction to intersect a key insertion hole; and the elastic holding member 20 comprising a pair of projecting parts 20a, 20a projected axially forward, and a connecting part 20b arranged in the key insertion hole to connect the projecting parts to each other, and holding the switching tumbler in a position not to interfere with an outer cylinder 11 by engaging at least one of the pair of projecting part with the switching tumbler. The holding member is held in the key insertion hole while the pair of projecting parts being elastically deformed in a mutually approaching direction by at least one of the switching tumbler and the key insertion hole when the projecting part is engaged with the switching tumbler.