Low-frequency noise properties of all-thin-film superconducting Nb-(constrictions)-NbN point contacts have been investigated. This type of contact can be regarded as a superconducting mesoscopic system, and its quasiparticle characteristic can be analyzed effectively Blonder, Tinkham and Klapwijk ( BTK) theory based on the Bogoliubov-de Gennes equation. We also discuss on white noise in Nb-(constrictions)-NbN point contacts, in the clean and ballistic limit. The temperature dependence of crossover voltages between thermal noise and shot noise in the ballistic system is in good agreement with calculated values.