An object of the present invention is to realize a loop through circuit, in an active connector, securely having a preferable mismatching attenuation characteristic and having a preferable signal transmission characteristic, with respect to an input port, an output port, and an internal port, without providing a special circuit outside the connector. A connector base part has the input port inputting an external signal, the output port outputting a loop through signal, and the internal port outputting a signal into a device. First and second matching circuits, an equalizer circuit, a dividing circuit, and a driving circuit are stored in the connector base part. The matching circuit is supplied with an external signal input from the input port. The dividing circuit divides a signal to be input to generate first and second divided signals, and outputs them to the internal port and the output port. The equalizer circuit compensates for a frequency characteristic and/or loss of a signal to be input. The driving circuit is provided between the dividing circuit and the matching circuit, and drives a transmission line to be coupled to the output port.