PURPOSE: To improve the measuring accuracy by detecting current between electrodes when foundry sand to measure water content is compressed with two electrode members.

CONSTITUTION: A weight 22 is moved properly to adjust and set the pressing force of a cylindrical member 11 made up of a conductor. When foundry sand to measure the water content is fed through a chute 29, it enters a groove defined by a cylindrical member 6 made up of a conductor and a disc members 7 and 8 made of an insulator at a lower end opening of the chute 26 and transferred in the direction of the cylindrical member 6 rotates while compressed under a fixed pressing with the cylindrical member 11 to increase the density thereof. Under such a condition, when a voltage is applied between the cylindrical membes 6 and 11, current runs according to the water contained in the foundry sand. Thus, the intensity of the current is detected to calculate the water content.