ESD protection device and manufacturing method for ESD protection device

A manufacturing method for an ESD protection device in which a cavity is provided within a multilayer substrate in at least one of a region positioned adjacent to or in a vicinity of a discharge portion of a first discharge electrode on an opposite side to a discharge auxiliary electrode and a region positioned adjacent to or in a vicinity of a discharge portion of a second discharge electrode on an opposite side to the discharge auxiliary electrode, the manufacturing method comprising:

• fabricating ceramic green sheets;
• preparing a conductive paste for the discharge electrode;
• preparing a mixed paste for the discharge auxiliary electrode;
• preparing a cavity forming paste that melts, evaporates, or dissolves in response to firing;
• forming, in a predetermined one of the ceramic green sheets, a through-hole that penetrates between front and rear principal surfaces of the one ceramic green sheet, and filling the mixed paste for the discharge auxiliary electrode in the through-hole;
• forming, in predetermined another one of the ceramic green sheets, a through-hole that penetrates between front and rear principal surfaces of the other one ceramic green sheet, and filling the cavity forming paste in the through-hole;
• applying the conductive paste for the discharge electrode, in a predetermined shape, onto at least one principal surface of each of predetermined still other ones of the ceramic green sheets;
• fabricating an unfired laminate by laminating the ceramic green sheets in a predetermined order;
• and
• fabricating the multilayer substrate by firing the unfired laminate.