We present a new generation of nanomechanical membrane-type surface stress sensor (MSS) chip, which has a two dimensional (2D) array of MSS on a single chip. The implementation of several techniques in design and microfabrication improves the sensitivity, achieving 3~4 times higher sensitivity than the first generation MSS chip and exceeding ~100 times sensitivity compared to a standard cantilever-type sensor. Since the integrated piezoresistive read-out can meet the practical requirements, such as small and simple without expensive peripheral devices, the MSS is one of the most promising transducers for nanomechanical sensing, providing various opportunities of practical applications in a wide range of fields, such as for the growing demands in medical, security, and environmental issues.