To facilitate operation to insert and fix a bolt after linking a bolt insertion hole of connection metal fittings suspended in a movable state from one end part of an insulator string and a bolt insertion hole on the side of an electric wire clamp member with each other.

There is provided a connection structure between a first metal member 15 which has one end part coupled to a support member 12, and a second metal member 30 which has a base end part fixed to the other end part of the fist metal member rotatably with a bolt. The first member includes a first bolt insertion hole 16a, a second bolt insertion hole 16b, and a lock pin 20, and the second metal member is provided with a bolt insertion hole 31 which communicates with the second bolt insertion hole, and a lock hook 18. The bolt insertion hole is set in a positional relation of being communicable with the second bolt insertion hole while the lock hook is locked to the lock pin.