The two-dimensional electrophoresis and Western blotting are widely used in comprehensive study of the proteome. In this system, proteins are separated by an isoelectric focusing and SDS-PAGE, and transferred to a membrane electrically, followed by the detection with immunoreactions. Generally both devices for electrophoresis and electroblotting are used independently. Researchers have to take out gel from the electrophoresis device, and set gel and membrane to electroblotter manually, and these procedures always lack reproducibility of the protein transfer efficiency and resolution, and also are complicated and time consuming. To solve these problems, we are developing a fully automatic operation system of gel electrophoresis and Western blotting with higher reproducibility in a shorter time. This system will make it possible to perform all processes automatically; sample introduction, isoelectric focusing, SDS-PAGE, blotting, and immunoreactions. (Researchers only have to set a sample, a gel tip and buffer solution on this device.) In this study, we developed an automated sequential system that makes possible to separate proteins in a gel electrophoresis (SDS-PAGE), followed by a continual electroelution, and blotting to PVDF membrane. We optimized the system condition, such as the gel concentration of SDS–PAGE, current of electroblotting (20-25mA), velocity of PVDF membrane movement, and the constitution of the buffer solution on this device. It was successful to obtain reproducible results on the transfer efficiency of proteins with a high resolution using this automated system, at the same level as a result obtained by the general manual protocol commonly used, and this system will be useful for the study of the proteins in biological materials.