There is provided a wire connection device including an outer frame that has a tubular shape, and a plurality of contacts that are provided in the outer frame, and that have a plurality of pairs of differential contacts to which a plurality of pairs of differential signals are respectively allocated, and a plurality of ground contacts each to which ground is allocated. When viewed from a direction along a central axis of the outer frame, the plurality of contacts are arranged side by side in two rows in a manner that the differential contacts of each pair can be adjacent to each other and in a manner that the number of the ground contacts adjacent to one of the differential contacts of each pair is equal to the number of the ground contacts adjacent to the other one of the differential contacts of the pair.