A wire connecting device for connecting and electrically communicating a first electrical wire and a second electrical wire can include: an electrical connector having a first end, a second end, and a concave portion between the first end and the second end, wherein the concave portion is configured for accommodating a second core wire of the second electrical wire; and a connecting member cooperating with the electrical connector and configured for guiding the first end and the second end of the electrical connector connected with the first electrical wire. A wire connection method using the wire connecting device can be further provided.