Fixing structure for vehicle lockset

The invention provides an installation structure of vehicle door lock which can prevent the falling off of installation part which installs the casing of vehicle door lock on the inner side board of the vehicle door and avoids the installation part from water corrosion. One of the two half-casing bodies made of synthetic resin and forming the casing is incorporated with a tubular installation tube for inserting a metal nut from an axial side. The nut comprises a cylinder part with a thread hole and a pair of clamping convex parts symmetrically formed with the cylinder axis and protruding fromthe cylinder to the outside of the radius direction. The inner surface of the installation tube is formed to enable the nut to insert into preset position axially and to carry out angular displacement operation along one side of circumference with preset angular displacement, thereby clamped with two clamping convex parts from both sides of the axis and preventing falling off of the nut. The other half-casing body is prov