According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer and a light emitting layer. The emitting layer is provided between the n-type layer and the p-type layer, and includes a plurality of barrier layers and a plurality of well layers, being alternately stacked. The p-side barrier layer being closest to the p-type layer among the plurality of barrier layer includes a first layer and a second layer, containing group III elements. An In composition ratio in the group III elements of the second layer is higher than an In composition ratio in the group III elements of the first layer. An average In composition ratio of the p-side layer is higher than an average In composition ratio of an n-side barrier layer that is closest to the n-type layer among the plurality of barrier layers.