Introduction The surface analytical techniques i r radiate an electron beam, an ion beam or X-ray on the surface of the sample for investigation of i t s morphology and physical characteristics based on the interactions between the beam and substances existing on the sample surface. To observe the sample morphology, an optical microscope and an electron microscope are mainly used. To study the sample characteristics, a wide range of techniques is available depending on the incident particles (beam) and the signals to be detected. They include Electron Probe Microanalysis (EPMA) , Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) . In recent years, electronic devices are frequently composed of organic compounds such as organic semiconductor, organic light-emitting diode (OLED) and organic film solar cell, and the use of them will be expected to further expand. It is increasingly important to inspect organic-compounds and their degradation mechanism in the products . Among sur f a c e analytical techniques, AES and XPS are capable of obtaining chemical bonding states or information on functional groups in chemical compounds, but those techniques have a difficulty in structural analysis of organic compounds. The TOF-SIMS is a mass spectrometry technique well known as a surface analytical technique. By using the dynamic SIMS, fragmentation of the molecular ions is likely to occur at ionization, thus making it difficult to apply SIMS to analyze organic compounds. Recently, techniques which utilize metallic clusters or gas clusters as a primary ion beam attached to TOF-SIMS have been succeeded to ionize more softly. These techniques are expected to expand the TOF-SIMS applications for organic compounds.