A light emitting device package comprising: a first substrate of a ceramic material having a first surface, a second surface, and two through holes, and a metal or a conductive film formed in each through hole; a second semiconductor substrate bonded to the first substrate, the second substrate having a light emitting device mounting hole, and a reflection film formed on a side wall surface of the mounting hole, wherein the second substrate has a first conductivity; two first electrodes arranged on the first surface, each first electrode being connected to the metal or the conductive film formed in an associated one of the through holes; two second electrodes arranged on the second surface, each second electrode being connected to an associated one of the first electrodes via the metal or conductive film in an associated one of the through holes; one light emitting device arranged in the mounting hole, and electrically connected to the first electrodes; and two diffusion layers each located in the second substrate and extending from a surface of the second substrate facing the first substrate into the second substrate to a depth which is less than the thickness of the second substrate, each of the diffusion layers having a second conductivity that is opposite to the first conductivity, wherein the two diffusion layers and the second substrate form two corresponding zener diodes, wherein each of the two zener diodes is electrically connected to the light emitting device via an associated one of the two first electrodes, wherein an insulating layer is disposed between the second substrate and each of the first electrodes, the insulating layer comprising through openings, a contact pad being provided inside of each of said through openings, each of the Zener diodes being electrically connected to an associated one of the first electrodes through an associated one of said contact pads. a first substrate of a ceramic material having a first surface, a second surface, and two through holes, and a metal or a conductive film formed in each through hole; a second semiconductor substrate bonded to the first substrate, the second substrate having a light emitting device mounting hole, and a reflection film formed on a side wall surface of the mounting hole, wherein the second substrate has a first conductivity; two first electrodes arranged on the first surface, each first electrode being connected to the metal or the conductive film formed in an associated one of the through holes; two second electrodes arranged on the second surface, each second electrode being connected to an associated one of the first electrodes via the metal or conductive film in an associated one of the through holes; one light emitting device arranged in the mounting hole, and electrically connected to the first electrodes; and two diffusion layers each located in the second substrate and extending from a surface of the second substrate facing the first substrate into the second substrate to a depth which is less than the thickness of the second substrate, each of the diffusion layers having a second conductivity that is opposite to the first conductivity, wherein the two diffusion layers and the second substrate form two corresponding zener diodes, wherein each of the two zener diodes is electrically connected to the light emitting device via an associated one of the two first electrodes, wherein an insulating layer is disposed between the second substrate and each of the first electrodes, the insulating layer comprising through openings, a contact pad being provided inside of each of said through openings, each of the Zener diodes being electrically connected to an associated one of the first electrodes through an associated one of said contact pads.