F_oF₁-ATPase is an active rotary motor, and generates three-ATP for each rotation. At saturated substrate concentration, the motor can achieve about 10³r.p.m, which means one motor can generate about 10⁵ATP molecules during 30 min. Here, we constituted a novel nanodevice with a molecular rotary motor and a "battery", F_oF₁-ATPase and chromatophore, and presented a novel method of sandwich type rotary biosensor based on ε subunit with one target-to-one motor, in which one target corresponds 10⁵ATP molecules as detection signals during 30 min. The target such as NT-proBNP detection demonstrated that this novel nanodevice has potential to be developed into an ultrasensitive biosensor to detect low expressed targets.