To provide a method of manufacturing a ceramic electronic component which allows easy manufacturing of ceramic electronic components of the same internal structure regardless of the frequency of using a box.

On a front surface of the box 1, an Ni screen for preventing the reaction between the box 1 and a ceramic element to be put on top thereof is placed. The ceramic element is put on top of the Ni screen. Under this condition, the box 1 is put into a sintering furnace and is sintered to form an Ni diffusion layer 11a in a prescribed depth from the Ni screen formed-side face of the box 1. After being used for sintering the prescribed times, the box 1 is fixed on a base 202 for machining with the Ni diffusion layer 11a-side face upwards, and is ground from the upper surface side by the thickness D of the Ni diffusion layer 11a using a grindstone 201.