Abstract: In connection with an electrode holder for immersion-type flow-type and attachment-type measuring systems in analytical chemistry, in particular for pH, conductivity, oxygen and chloride measurements, or the like, comprising an outer pipe in which an inner pipe carrying the measuring probe is supported in axially sliding relationship, and a stopcock blocking the supply of measuring agent by means of a plug of the stopcock when the inner pipe is retracted from the measuring agent it is proposed to leave the plug open on one side in the area of its passage channel and to have a remaining rear wall of the passage channel facing the supply opening of the measuring agent.