To certainly detect the presence of the adhesion of the electrolyte of a living body or the disconnection-contact failure of a sensor part, by combin ing a sensor constituted of two juxtaposed conductors and an electric resistance body.

The sensor for detecting the electrolyte of the living body is equipped with two juxtaposed conductors C1 and C2, the electric resistance body 18 being connected across the conductors and a base substrate BP having two conductors C1 and C2 and the electric resistor 18 arranged thereto. The detector equipped with a determining means for determining the state of the detection sensor is also disclosed.