A flat conductor electric connector mounted on a circuit board and electrically connected to a front end side portion of a band-shaped flat conductor extending in a front-back direction, comprising: multiple terminals in such a shape that metal plate members are bent in a plate thickness direction thereof; and a housing holding, by insert molding, the multiple terminals arrayed in a terminal array direction which is a band width direction, wherein each of the multiple terminals has, at least at one end portion in the front-back direction, a holding target portion held on the housing and an extending portion extending from the housing and formed with a mounting portion to be mounted on the circuit board by soldering, and the holding target portions adjacent to each other and the extending portions adjacent to each other are arrayed and positioned in the terminal array direction. The mounting portion includes an opening to receive a pin of a molding device.