CHARGING PART MONITORING DEVICE

PROBLEM TO BE SOLVED: To provide a charging part monitoring device which achieves a rational structure of a sensor slave unit including a power supply part that generates an operation power supply for itself, thereby contributing to a reduction in the number of components of the device.SOLUTION: A sensor slave unit 11 includes a power supply part (electrode part 31) of electrostatic capacity partial pressure type that obtains a power supply by the action of an electric field generated in a charging part of a high pressure bus line. An attachment notch 12a for attaching the sensor slave unit 11 to the charging part is integrally configured with respect to a base plate 12 that uses the base plate 12 as a first electrode and a conductor layer 15a of a printed circuit board 15 as a second electrode. The attachment notch 12a is also used as an attachment part.