Contact connection structure for removing oxide buildup

A contact connection structure comprising:

• a first contact portion including an indent portion spherically protruding toward a second contact portion, the first contact portion including a plating layer formed on an outer surface of the first contact portion including the indent portion;
• and
• the second contact portion including a plating layer formed on a surface of the second contact portion, wherein
• the indent portion of the first contact portion and a contact surface of the second contact portion are slidable on each other,
• the contact surface of the second contact portion includes an oxide-film shaving portion having an annular arc portion that makes contact along a circumference portion of the indent portion, and
• the indent portion of the first contact portion is in contact with the oxide-film shaving portion of the second contact portion at a terminal insertion completed position.