We have developed a new planar-type ion channel biosensor with a silicon-on insulator substrate and a cell culture function. Fibronectin is coated on the substrate surface to promote cell growth in this sensor. A transient receptor potential vanilloid type 1 (TRPVl) channel-expressing HEK293 cell is positioned on the micropore of the SOI sensor chip and incubated. Although the seal resistance was quite small, 10-20 M ohm, compared with that of the conventional pipette patch-clamp method, the signal-to-noise level was sufficiently high. However, a much lower noise level is required for observing the opening and closing of fewer than 30 channels.