An automatic titration was performed by a home-made automatic control system adopting a micro pH electrode as its sensing part in microdiffusion-based volatile basic nitrogen (VBN) analysis. The micro electrode was considered to be adequate for automatic VBN analysis because of its small sensor size, low immersion depth and unbreakable body. Six pork samples in different degree of freshness were analyzed both manually and automatically. The data from automatic titration were not significantly different from those taken by manual titration even at 15% significance level. The correlation coefficient was 1.000.