A nanometer-scale structure of metal/Langmuir-Blodgett (LB) film/metal is realized using an atomic force microscope (AFM) with an electrically conducting probe. In this configuration, increase in conductance can be induced at any point in the LB film by application of a voltage pulse. Clear spots are observed in the current image at the points where voltage pulses are applied, while no specific feature such as protrusions or holes is observed in the AFM image obtained simultaneously. These results show that the conductance of the LB film changes without pit formation in the LB film or metal cluster deposition from the tip of the probe. The transition takes place within 1 μs, and the transition can be induced at several thousand points, at least, without tip degradation. These facts demonstrate the feasibility of constructing information storage devices with high density.