A biosignal detecting apparatus is disclosed. The biosignal detecting apparatus includes a pair of detecting electrodes which is attached to a human body for detecting a biosignal from the human body, a biosignal detecting circuit which receives the biosignal detected by the detecting electrodes and processes the detected biosignal, a transmitting electrode which is attached to the human body for transmitting the biosignal processed by the biosignal detecting circuit via the human body to an external apparatus and for transmitting a radio wave generated by a circuit in the biosignal detecting apparatus, and a circuit connected to one of the detecting electrodes which circuit receives the radio wave transmitted from the human body via the transmitting electrode and executes impedance matching between the biosignal detecting apparatus and the human body based on the received radio wave transmitted from the human body via the transmitting electrode.