Yamasinaium noduligerum is a Japanese fungivorous millipede that is usually found on decaying logs fallen on the forest floor. Here we present observations on paternal egg-brooding behavior in this species. At the end of May to early June, we found males with eggs on the bark of the underside of fallen decaying logs and in old burrows and galleries excavated by wood-dwelling insects under the bark of the logs. The males showed a typical brooding posture where they curl the anterior part of the body around the egg mass. The egg masses contained, on average, 30.2 ± 13.7 (SD) eggs. The brooding males showed no aggressive responses when disturbed.