Fast electron transfer between laccase (Lac) and single-walled carbon nanotubes (SWCNTs) can be achieved at a cholate-modified SWCNT interface. Furthermore, the catalytic reduction of O 2 starts at a high potential, close to the equilibrium redox potential of the O 2 /H 2 O couple. A sodium cholate (SC)-modified electrode interface provides suitable conditions for Lac direct bioelectrocatalysis. In the present study, the SC promotional effect in Lac direct bioelectrocatalysis was investigated using various types of electrode materials. The fully hydrophilic surface of indium tin oxide and an Au electrode surface did not show a SC promotional effect, because SC did not bind to these surfaces. A carbon surface with a large number of defects was unsuitable for SC binding because of hydrophilic functional groups at the defect sites. Carbon surfaces with few defects, for example, basal-plane highly oriented pyrolytic graphite (HOPG), gave a SC promotional effect.