PURPOSE: To secure electrical conductivity inside an electrode main body for smooth measurements by easily removing bubbles existing inside a tube or the like for smooth circulation of an internal liquid and stabilization of outflow pressure.

CONSTITUTION: This electrode body consists of an electrode main body 1 with a tube 7 connected to its internal liquid replenishing hole 6a so that an internal liquid for a reference electrode is supplied via the tube 7 into an internal liquid chamber 2 inside the electrode main body 1 from the outside. Time main body has a through hole 10 therein which communicates with the internal liquid chamber 2 and a plug 13 which can be handled to close the through hole 10 during measurement and to vent the internal liquid chamber 2 to atmosphere via the through hole 10 during removal of bubbles existing in the tube 7, etc.