A highly sensitive biosensor that uses a smaller amount of sample for measurement
is described. The biosensor includes a first insulating base plate having a working
electrode, a second insulating base plate having a counter electrode opposed to
the working electrode, and a reagent layer containing at least an oxidoreductase.
The biosensor further includes a sample supply pathway formed between the first
and second insulating base plates, where the working electrode, counter electrode
and reagent layer are exposed to an inside of the sample supply pathway, and the
distance between the working electrode and the counter electrode is 150 m
or less.
