An apparatus and method for measuring the properties of underground water are disclosed. The device comprises a measuring apparatus with a measuring sensor for measuring the properties of the underground water, a pair of expandable and contractible packers arranged above and below the measuring apparatus, a transmitting means for sending measurement signals from the measuring apparatus, and a receiving means located at the ground surface for receiving the measurement signals from the transmitting apparatus. The method of the present invention comprises the steps of placing a measurement apparatus with a measuring sensor in a bored hole at a desired depth, arranging a pair of packers so that the measuring sensor is interposed therebetween, pumping water to the ground surface from the space between the two packers, and comparing the properties of the water pumped to the surface with the properties of the water measured with the above-mentioned measuring sensor.