A terminal can be slidably held while liquid-tightness and airtightness are steadily maintained. Included are a base part where a rear through-hole is formed; a terminal storage case which includes a front plate part where a front through-hole is formed, and in which a rear end is connected to the base part; a terminal that includes an axis part, a contact part, and a flange, the rear end proximity part of the axis part being slidably inserted into the rear though-hole, and the contact part being slidably inserted into the front through-hole; an energizing member that is mounted on the circumference of the axis part and energizes the flange to a front; and a cylindrical sealing member that includes a first sealing member interposed between the tip end of the energizing member and the flange, a second sealing member interposed between the rear end of the energizing member and the base part, and a central cylinder for connecting the first sealing member with the second sealing member.