Ceramic electronic device and mounting substrate

A ceramic electronic device comprising:

• a multilayer chip having a plurality of dielectric layers and a plurality of internal electrode layers that are stacked, and having a first main face and a second main face that face each other in a stacking direction and have a rectangular shape in a planar view;
• two external electrodes each of which extends from the first main face to the second main face at each of two diagonal corners of the rectangular shape, the two external electrodes being spaced from each other, each of the two external electrodes being connected to a part of the plurality of internal electrode layers;
• and
• a conductor that is provided on the first main face, the second main face or both of the first main face and the second main face, is spaced from the two external electrodes, and is provided in a region which includes an intersection point of perpendicular bisectors of two adjacent sides of the rectangular shape,
• wherein the conductor extends from a first diagonal corner of other two diagonal corners to a second diagonal corner of the other two diagonal corner on the first main face, the second main face, or both of the first main face and the second main face.