An in-vehicle antitheft device and a central authentication device can improve a convenience of use of a user while maintaining a high security, which is a merit of a central-type authentication system. A use of a first group of vehicle functions, which has not been permitted, is permitted when an authentication by an in-vehicle local collation part is completed in agreement. A request signal of requesting a user authentication is transmitted to a central authentication device through a communication line. A use of a second group of vehicle functions, which have note been permitted, is permitted when the user authentication is completed in agreement in the central authentication device.