Passage detection apparatus of object

A passage detection apparatus of an object that can detect a passage of an object in a specific space, comprising:

• a vibration generating source;
• a sensor unit that is arranged at a position corresponding to the vibration generating source across the specific space, and configured to be capable of generating an output according to the vibration, which propagates through a medium in the specific space, from the vibration generating source;
• and
• a determination unit that determines the passage of the object in the specific space on the basis of the output from the sensor unit, wherein
• the sensor unit includes:
• a vibration plate made of a plate-like dielectric layer and constitutes an outer wall enclosing the specific space;
• a first detection electrode formed to the vibration plate;
• a support plate arranged parallel to the vibration plate with a predetermined gap;
• and
• a second detection electrode formed on an inner surface, which faces the vibration plate, of the support plate, and arranged parallel to the first detection electrode, wherein
• the determination unit is configured to determine the passage of the object in the specific space on the basis of an electrostatic capacitance between the first detection electrode and the second detection electrode.