An electrode package includes an electrode pad to be attached to a subject, the electrode pad having a gel layer, a lead wire having one end electrically coupled to the gel layer, and a packaging cover having an opening portion, the opening portion being sealed such that the electrode pad and a part of the lead wire are housed inside the packaging cover. A sealing width in at least a part of a section where the packaging cover is sealed together with the lead wire is narrower than a sealing width in a section where only the packaging cover is sealed. A sealing apparatus is configured to seal the packaging cover.
