The Maebashi Tenjinyama Tomb is a keyhole-shaped tumulus with a length of 130 m in Gokan-machi, Maebashi, Gunma. These artifacts were excavated from the clay burial chamber when an urgent archaeological survey was conducted prior to an urban development plan to be implemented in 1968 to 1969. Now, the tumulus is preserved only the surrounding of the chamber by Gokan-machi, Maebashi. Judging from excavated hajiki (reddish brown unglazed earthenware), it is estimated that the tumulus was built in the early Tumulus period around the 4th century. The artifacts excavated include the following: 5 bronze mirrors, 4 stone objects in the shape of a spindle, 1 sokanto sword (a sword with a ring at the end), 6 single-edged iron swords, 12 double-edged iron swords, 30 bronze arrowheads, a set of iron arrowheads, 3 iron axes, 23 yariganna (carving instrument), 3 iron chisels, 1 iron tosu (thin small sword) and 6 iron hooks. Most notably among them is a diversity of bronze mirrors in a good state of preservation including sankakubuchi-shishinshiju-kyo, sankakubuchi-goshinshisiju-kyo, sandanshiki-shinsen-kyo, nikinniju-kyo and henkei-jukei-kyo. The sankakubuchi-shishinshiju-kyo bronze mirrors that were cast using the same mold as this one include those excavated from Mochida #48 tumulus in Takanabe-cho, Miyazaki and those from Kurayoshi, Tottori. The sankakubuchi-goshinshiju-kyo bronze mirrors that were cast using the same mold as this one include those excavated from the Chausuyama Tomb in Sakurai, Nara and those from the Kurozuka Tomb in Tenri, Nara. These are extremely valuable materials in that they showcase the overall picture of burial accessories of the early Tumulus period in the Kanto region.