A power converter for a railroad vehicle includes a first fin and a second fin having outer shapes different from each other as viewed in an alignment direction. On both ends of the first fin and the second fin in a running direction, non-overlapping regions in which the first fin and the second fin do not face each other in the alignment direction are located so as to sandwich an overlapping region, in which the first fin and the second fin face each other in the alignment direction, therebetween.