We have developed plasma chemical vaporization machining by using a microelectrode for the fabrication of small complex-shaped optical surfaces. In this method, a 0.5\text{\hspace{0.17em} mm} diameter pipe microelectrode, from which processing gas is drawn in, generates a small localized plasma that is scanned over a workpiece under numerical computer control to shape a desired surface. A \text{12 \hspace{0.17em} mm}\times \text{12 \hspace{0.17em} mm} nonaxisymmetric mirror with a maximum depth of approximately \text{3 \hspace{0.17em} μm} was successfully fabricated with a peak-to-valley shape accuracy of \text{0 .04 \hspace{0.17em} μm} in an area excluding the edges of the mirror. The average surface roughness was \text{0 .58 \hspace{0.17em} nm} , which is smooth enough for optical use.