An electric source control apparatus has: a determining device for determining whether a converter operates in a first mode or a second mode, wherein the first mode prioritizes increase of efficiency of the electric power conversion than the second mode does and the second mode prioritizes suppression of increase of element temperature of the switching element than the first mode does; and a controlling device for controlling the converter so that (i) a switching pattern becomes a first pattern, if the converter operates in the first mode and (ii) the switching pattern becomes a second pattern, if the converter operates in the second mode, wherein the first pattern is capable of increasing the efficiency of the electric power conversion more than the second pattern is and the second pattern is capable of suppressing the increase of the element temperature more than the first pattern is.