Socket and inspection socket

A socket comprising:

• a base portion that includes a first base portion and a second base portion both electrically conductive and assembled so as to overlap each other in an upper-lower direction, the base portion being provided with a through hole penetrating through the first base portion and the second base portion in the upper-lower direction;
• and
• a contact pin that is inserted into the through hole and is connected to a terminal of a first electric component at an upper end and to a terminal of a second electric component at a lower end when in use to electrically connect the first electric component and the second electric component together, wherein:
• the base portion
• holds the contact pin through an insulation member in the through hole of the first base portion,
• further includes a first stepped portion in which a diameter on a side of the second base portion is smaller than a diameter on a side of the first base portion at a boundary portion between the through hole of the first base portion and the through hole of the second base portion,
• restricts downward movement of the insulation member with the first stepped portion,
• further includes, in the through hole of the first base portion, a second stepped portion in which a diameter on a distal side apart from the boundary portion is reduced from a diameter on a proximal side close to the boundary portion, and
• restricts upward movement of the insulation member with the second stepped portion,
• the insulation member is a cylindrical body extending in the upper-lower direction while surrounding an outer periphery of the contact pin, and
• the cylindrical body including a protruding portion that protrudes outward in a part of the cylindrical body in the upper-lower direction and that is in contact with the first-step stepped portion and/or the second-step stepped portion.