A heater for use in an image heating apparatus includes a substrate, first and second conductors provided on the substrate, and heating elements. The heating elements are arranged between, and electrically connected in parallel to, the first and second conductors. When n denotes a number of heating elements, connected to one second conductor, in one row of the heating elements, a width L denotes a sum (n×Wh) of widths, as seen in a longitudinal direction of the substrate, of shortest current paths of all respective heating elements connected to the one second conductor plus a sum of widths, as seen in the longitudinal direction, of respective gaps between adjacent shortest current paths, and a ratio R denotes a ratio of the sum (n×Wh) of widths to the width L, the heating elements are configured so as to satisfy 0.54≤the ratio R