Time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging provides ten-nanometer-scale chemical images of biodevices. It is one of the most sensitive surface analysis methods and has recently been applied in life sciences. TOF-SIMS is useful for the evaluation of biodevice surfaces, because it provides ten-nanometer-scale mapping and chemical structures of immobilized proteins on devices. In addition, TOF-SIMS requires no pretreatment of samples, such as labeling with a fluorescent probe or coating with metallic thin films. In this paper, the principles of TOF-SIMS and data analysis methods are introduced, and some examples of biodevice observation with TOF-SIMS are described.