We have developed a mesoscale/nanoscale discharge plasma generator, which consists of two electrodes with an ultrasmall, gap on the mesoscale/nanoscale controlled by two piezoelectric actuators and a Langmuir plasma probe system housed in a high-pressure chamber. By means of this apparatus, the mesoscale/nanoscale N-2 and air plasmas in the range between 10 mu m and 800 nm have been realized. Moreover, Langmuir probe measurements revealed an interesting characteristic, namely a non-equilibrium cold nature of the plasmas, even in high-pressure environments.