The nonextensivity for a general quantum dissipative system driven by an external force is investigated. The dynamics of the system is characterized by a nonextensivity parameter q which indicates the degree of departure from extensivity for the system. The wave function of the system in the coherent state is derived with the aid of the linear invariant operator which obeys the Liouville–von Neumann equation. It is confirmed that, although the corresponding quantum energy dissipates with time like the classical energy, its time behavior is somewhat different from that of the usual dissipative systems depending on the scale of nonextensivity. The rate of such a dissipation becomes slightly larger as q increases. The effects of nonextensivity on other quantum characteristics of the system, such as fluctuations and uncertainty relations for canonical variables, are also analyzed rigorously. It is shown that the authors' results in the nonextensive regime recover to those of the well known standard ones in the limit q→1.