The electroencephalogram electrode unit for small animals includes a base that covers the scalp or brain surface of a small animal and has a plurality of through holes and a plurality of electrodes. Each of the plurality of electrodes is inserted into each of the plurality of through holes, and each of the plurality of electrodes is equipped with an insulating tube, an electrode section disposed within the tube, an extraction conducting wire that is connected to the electrode section and extracts the EEG signal to outside, and a paste that is filled within the tube. The tube is installed in the through hole in a manner of standing upright from the scalp or brain surface, and the electrode section is formed in the form of a wire and is disposed, in a manner of standing upright from the scalp or brain surface, within the paste filled within the tube.