A surface-mount negative-characteristic thermistor includes a ceramic body composed of a semiconductor ceramic material including at least one of Mn, Ni, and Ti; external electrodes disposed on surfaces of the ceramic body; and plating films disposed on surfaces of the external electrodes. When the molar quantity of Mn in the semiconductor ceramic material is represented by a and when the molar quantity of Ni in the semiconductor ceramic material is represented by b, the molar ratio of Mn to Ni is in the range of 55/45≦a/b≦90/10, and when the total molar quantity of Mn and Ni in the semiconductor ceramic material is defined as 100 parts by mole, the content of Ti is in the range of about 0.5 parts by mole to about 25 parts by mole.