A semiconductor light emitting device capable of precisely detecting a cleavage position is provided. A second light emitting device is layered on a first light emitting device. The second light emitting device has stripe-shaped opposed electrodes that are respectively arranged oppositely to respective p-side electrodes of the first light emitting device and electrically connected to the p-side electrodes of the first light emitting device, connection pads respectively and electrically connected to the respective opposed electrodes, a connection pad electrically connected to a p-side electrode, and marks arranged with one end in the plain face of cleavage face S3 or cleavage face S4 on an insulating layer formed on the side of a second substrate facing to a first substrate.