Abstract: To provide a sensing device that holds a piezoelectric sensor and a channel forming member placed on the sensor in a closely contacted state while maintaining a shape of space of a passage space formed inside the device. In a sensing device 1100 that senses a substance to be sensed based on a variation in an oscillation frequency caused by an absorption of the substance to be sensed in an absorption layer provided on a piezoelectric resonator 1720 of a piezoelectric sensor 1700, a holding member 1600 holds the piezoelectric sensor 1700 and a channel forming member 1730 that forms a passage space through which a sample fluid passes on an upper surface side of the sensor, in a vertically stacked state. A cover member 1510 is placed on the channel forming member 1730, and a pressing part 1350 which is raised/lowered by a first raising/lowering mechanism 1300 presses the cover member 1510 placed on the channel forming member 1730 downward with a previously set force.

Abstract: It is possible to determine the presence of bacteria in a sample solution in a shorter period of time without changing a conventional incubating method. Bacteria in a sample solution are incubated in, for example, a sterilized agar medium 10 having a layer thickness of 0.1 ?m to 1 ?m formed on an electrode of a crystal resonator 2, and an oscillation frequency is measured. When the bacteria proliferate, the mass of the entire crystal resonator 2 increases, and the oscillation frequency decreases. Therefore, by monitoring presence of such a change over time, presence of bacteria in the sample solution can be determined quickly.

Abstract: To provide a sensing device having a high processing power and capable of high-accuracy measurement. It is determined whether or not an oscillation frequency is stabilized while a buffer solution is supplied to a quartz-crystal resonator 4 from a syringe pump 10. When it is determined that the frequency is stabilized, a second valve 14 is switched to a sample solution supply mode to supply a sample solution in an injection loop 14a to the quartz-crystal resonator 4. An instant at which the sample solution reaches the quartz-crystal resonator 4 and an instant at which the sample solution finishes passing through the quartz-crystal resonator 4 are automatically found based on a supply flow rate of the buffer solution, a volume of the injection loop 14a, a volume of a supply channel supplying the sample solution to the quartz-crystal resonator 4, and an instant at which the second valve 14 is switched to the sample solution supply mode.