The invention relates to: a light-emitting device which uses a blue light-emitting silicate-based phosphor of the following formula 1 and also uses wavelength capable of directly exciting Eu2+ ion with excitation wavelength; and to a display device employing the light-emitting device. In addition, this invention provides a silicate-based phosphor represented by the following formula 2 and a light-emitting device or a display device employing the silicate-based phosphor. When excited at 254nm, a phosphor of (SrxBay)MgSi2O8:Euz (x/y xBay)MgSi2O8:Euz (x/y >1). Moreover, the phosphor of (SrxBay)MgSi2O8:Euz (x/y <1) exhibits high luminance even in much higher Eu concentration since the trend in the concentration of conventional (SrxBay)MgSi2O8:Euz and Eu is different.
