A protection element and a secondary battery device employing the protection element are provided for stably retaining a flux on a soluble conductor at a predetermined position, so as to enable appropriate blowout of the soluble conductor in the event of an abnormality. The protection element has a soluble conductor which is disposed on an insulation baseboard, and which is connected to a power supply path of a device targeted to be protected, and which causes a blowout when a predetermined abnormal electric power amount is supplied. A flux is coated on a surface of the soluble conductor, and an insulation cover member is mounted on the baseboard and covers the soluble conductor. The protection element also includes a stepped portion for retaining the flux at a predetermined position in contact with the flux, and the stepped portion is formed opposite to the soluble conductor on an interior face of the insulation cover member.