A heater connectable with an electric power supply portion having a first terminal and a second terminal , said heater comprising: an elongate substrate ; a first electric contact (641a or 641b) provided on said substrate and electrically connectable with the first terminal ; a plurality of second electric contacts (651a, 661a or 651b, 661b) provided on said substrate and electrically connectable with the second terminal ; a first electroconductive line extended in a longitudinal direction of said substrate and electrically connected with said first electric contact ; a plurality of second electroconductive lines (650, 660a or 660b) extended in the longitudinal direction of said substrate and electrically connected with each of said second electric contacts (651a, 661a or 651b, 661b); a plurality of electrodes including a plurality of first electrodes electrically connected with said first electric contact (641a or 641b) and a plurality of second electrodes electrically connected with said second electric contacts (651a, 661a or 651b, 661b), respectively, said first electrodes and said second electrodes being arranged alternately with predetermined gaps in a longitudinal direction of said substrate ; and a heat generating layer provided on said plurality of said electrodes and configured to generate heat in an area between adjacent first and second electrodes by electric power supply between said adjacent first and second electrodes , wherein a distance between free ends of said adjacent first and second electrodes is larger than a width of said heat generating layer in a widthwise direction perpendicular to the longitudinal direction, wherein only said first electroconductive line is provided in one end side of the substrate relative to said heat generating layer in the widthwise direction and said second electroconductive lines are provided in the other end side of the substrate. an elongate substrate ; a first electric contact (641a or 641b) provided on said substrate and electrically connectable with the first terminal ; a plurality of second electric contacts (651a, 661a or 651b, 661b) provided on said substrate and electrically connectable with the second terminal ; a first electroconductive line extended in a longitudinal direction of said substrate and electrically connected with said first electric contact ; a plurality of second electroconductive lines (650, 660a or 660b) extended in the longitudinal direction of said substrate and electrically connected with each of said second electric contacts (651a, 661a or 651b, 661b); a plurality of electrodes including a plurality of first electrodes electrically connected with said first electric contact (641a or 641b) and a plurality of second electrodes electrically connected with said second electric contacts (651a, 661a or 651b, 661b), respectively, said first electrodes and said second electrodes being arranged alternately with predetermined gaps in a longitudinal direction of said substrate ; and a heat generating layer provided on said plurality of said electrodes and configured to generate heat in an area between adjacent first and second electrodes by electric power supply between said adjacent first and second electrodes , wherein a distance between free ends of said adjacent first and second electrodes is larger than a width of said heat generating layer in a widthwise direction perpendicular to the longitudinal direction, wherein only said first electroconductive line is provided in one end side of the substrate relative to said heat generating layer in the widthwise direction and said second electroconductive lines are provided in the other end side of the substrate. <EOS>