The present invention is for the purpose of installing a wireless transmitter in a transmitting unit of a bioelectric signal measuring device and changing electrodes to be attachable/detachable in order to: prevent the usable distance of the bioelectric signal measuring device from being restricted by limitations in the length of electric wire between a transmitter and a receiver, prevent the electric wire impeding an operation by blocking the field of vision during the operation, and reduce the danger of a disconnected electric wire. The present invention provides a bioelectric signal measuring device comprising: an insulation film capable of being attached to the outer peripheral surface of a bio catheter that is inserted into an opening of the human body a plurality of thin film electrodes arranged to contact muscle or nerve regions at which a portion of the bio catheter is located a transmitter for wirelessly transmitting a bioelectric signal scanned by the thin film electrodes conductive wire electrically connecting the thin film electrodes to the transmitter and a battery for operating the transmitter, wherein the electrodes, the transmitter, the conductive wire, and the battery are disposed on the insulation film. Also provided is a bioelectric signal measuring device configured of a head portion having a broad surface area and a tail portion connected to the head portion, the device comprising: an insulation film capable of being attached along the length of a bio catheter that is inserted into the human body a plurality of thin film electrodes disposed on the head portion that is the opposite surface to the insulation film attached on the bio catheter, and arranged to contact muscle or nerve regions at which a portion of the bio catheter is located and conductive wire located on the tail portion of the insulation film, and having one end electrically connected to the thin film electrodes and the other end connected to the terminal end of the tail portion.La
