<p>During the past 40&#xa0;years, bioelectrochemistry and bio-electroanalytical chemistry have developed. Especially, after the 1970s and 80s, protein electrochemistry has changed dramatically, because direct rapid electron-transfer reactions of metalloproteins were found to be observed on simple solid modified electrodes. The surface structures of such functional modified electrodes have also been studied at the atomic and/or molecular level using STM images on the single crystal surfaces to understand the roles of the surface structures. Since then, various electroanalytical techniques have been used to apply to analyze electrochemical behavior of important metalloproteins (i.e., cytochrome c, myoglobin, and ferredoxin) to understand the fundamental origins of their biological functions. In this short review, some of the achievements at the early stage of recent bioelectrochemistry of biologically important metalloproteins to analyze functions of biomolecules and their promising applications to prepare some biological devices, such as sensors and bio-fuel cells, are introduced based on research activities so far done in our group together with brief prospects.</p> Graphical abstract <p></p>