An axle bearing system includes a bearing portion which includes an inner ring, an outer ring and a plurality of rolling elements which are interposed between the inner ring and the outer ring and which is installed on a hub shaft with seal portions which are each formed by a slinger, a core metal and a non-conductive seal provided therebetween mounted in annular opening portions formed between the inner ring and the outer ring. A conductive body is attached to the seal portion so as to provide an electrical conducting state between the outer ring and the inner ring.