Decay properties of an isotope $^{266}$Bh and its daughter nucleus $^{262}$Db produced by the $^{248}$Cm($^{23}$Na, 5textit{n}) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. $^{
266}$Bh was clearly identified from the correlation of the known nuclide, $^{262}$Db. The obtained decay properties of $^{266}$Bh and $^{262}$Db are consistent with those observed in the $^{278}$113 chain, which provided further confirmation of the discovery of $^{278}$113.
