Abstract: An indium borate phosphor of this invention is represented by formula (In.sub.l-a-b-c-d Tb.sub.a Eu.sub.b Sm.sub.c M.sub.d)BO.sub.3 wherein[1] if b.noteq.0 and c.noteq.0,1.times.10.sup.-6 .ltoreq.a.ltoreq.1.times.10.sup.-20<b.ltoreq.1.times.10.sup.-10<c.ltoreq.1.times.10.sup.-31.times.10.sup.-7 .ltoreq.d.ltoreq.1.times.10.sup.-2[2] if b=c=0,1.times.10.sup.-6 .ltoreq.a.ltoreq.1.times.10.sup.-11.times.10.sup.-7 .ltoreq.d.ltoreq.1.times.10.sup.-2and M is at least element selected from the group consisting of Ti, P, Si, and Ge. This phosphor has a higher bonding force between BO.sub.3 ions and ions of In or any other contained metal than that of a conventional indium borate phosphor. As a result, the current-brightness and burning characteristics of the indium borate phosphor can be greatly improved.