To provide a cylinder lock which can be manufactured at a low cost by using synthetic resin and prevented from being broken to extend the life of a product.

A cylinder lock has a cylindrical case, a lock mainbody inserted into the case and provided with a lock shaft hole in the direction of a center axis and plural pin holes therearound in the axial direction, a lock shaft inserted into the lock shaft hole, provided with a flange at the upper part and arranged with the flange having the lower face matched to the upper face of the lock mainbody 4, and a magnet pin tumbler inserted into the pin hole. The lock mainbody 4 is formed with a metal upper lock mainbody 5 and a synthetic resin lower lock mainbody 6, the lower lock mainbody 6 being insert-molded of synthetic resin by using the upper lock mainbody 5 as an insert. The upper lock mainbody is formed by die casting metal or punching a metal plate into a preset shape.