This paper reports the sensitivity of cantilever biosensor with liposome as sensing biomolecules im-mobilized on the cantilever surface is improved by incorporating cholesterol in phospholipid mem-brane of DPPC liposome. We especially investigate whether incorporating cholesterol in the mem-brane is effective to influence and improve the sensitivity for Aβ protein as a causative agent of Alzheimer's disease (AD). Consequently, the sensitivity of the cantilever sensor is significantly im-proved as 50-nM Aβ(1-40) has been detected by the incorporation of cholesterol. This result implies that the sensor has the possibility to detect Aβ(1-40) in plasma of AD patients.