To easily fit a decorative ring into a housing of a cylinder lock by a "fingertip method".

This lock for a door is characterized in that: parts to be engaged, which are formed on the outer peripheral wall of the housing, are a plurality of locking grooves formed in a recessed shape at predetermined intervals in the circumferential direction of the outer peripheral wall; and a plurality of engaging arms, which are elongated toward an internal space, which have engaging pawl pieces capable of being each engaged with the locking grooves in fitting and which have the elastic deformation or elastic return function of being displaced by virtue of the property of a material itself, are formed at the leading end of the decorative ring.