Abstract: Disclosed is an instrument for measuring living body components, which has (i) a fine tube having at one end thereof a connection portion to be connected to an indwelling needle or indwelling catheter and an infusion portion, from which at least a blood anticoagulant solution can be infused, (ii) a fine linear sensor for measuring living body components, extended from the inferior of the fine tube to the outside through the connection portion, and (iii) a mechanism for introducing blood at least into the interior of a fine tube portion of the indwelling needle or catheter intermittently or periodically when the indwelling needle or catheter is connected to the fine tube and kept in the blood vessel and then discharging blood into the blood vessel. A sensing portion of the sensor is located within the fine tube portion of the indwelling needle or catheter when the indwelling needle or catheter is connected to the connection portion of the fine tube.

Abstract: Disclosed is a metal electrode for a living body, which comprises a noble metal wire an an insulating covering layer formed around the periphery of the noble metal wire. At least a part of the portion of the insulating covering layer falling in contact with the noble metal wire is composed of a crosslinked epoxy resin. The outermost layer of the insulating covering layer is composed of a polyurethane. Either or both of a part of the tip end and side face of the metal electrode is directly covered with a polyurethane porous membrane instead of the insulating covering layer.