The evoked spinal cord potential monitoring apparatus of the present invention includes: a pair of electrodes 14; and a holding section 12 for holding the pair of electrodes 14, a tip section of each of the electrodes 14 being extended outwards from an end of the holding section 12, and the electrodes 14 being movable relative to the holding section 12. A hook section 15 engageable to an intercostal nerve is provided at the tip section of each of the electrodes 14, and the electrodes 14 or the holding section 12 is moved while the hook section 15 is coupled to the intercostal nerve such that the hook section 15 and the holding section 12 are able to hold the intercostal nerve therebetween. The apparatus requires no preoperative preparation, is capable of coping with an emergency case, and further, is unsusceptible to the influence of anesthetics.