The invention relates to a grid sensor comprising wiry electrodes for measuring the electroconductivity of a flow medium in the cross-section of a pipeline. The invention can be especially applied where the flow medium flows at a high pressure and at high temperatures. According to the invention, each electrode wire (3) is mechanically connected to a spring (2) on one side by means of an insulating bead (4), said spring being arranged in a hole in the sensor body having an axis which is oriented in the tensioning direction of the wire, and fixed to the sensor body in this position. Each electrode wire on the side opposing the spring (2) is covered with an insulating tube (6) arranged in an outwardly guided channel in the sensor body. The insulating tube ends inside said channel, in a cavity (7) filled with a sealing material. Neither the insulating bead (4) on one side nor the insulating tube (6) on the other side are located in the cross-section wherein the measurement is to be carried out.
