According to one embodiment, in a semiconductor light emitting device, a semiconductor laminated body is made by laminating, in order, a first semiconductor layer of a first conductivity-type, a semiconductor light emitting layer and a second semiconductor layer of a second conductivity-type. The semiconductor laminated body includes a plurality of trenches arranged in a periodical manner to penetrate through the second semiconductor layer and the semiconductor light emitting layer and reach the first semiconductor layer. An insulating film is buried into the trenches, and has transparency to light emitted from the semiconductor light emitting layer. A first electrode is electrically connected to the first semiconductor layer. A second electrode covers an upper surface of the second semiconductor layer.