A semiconductor light emitting device includes a first layer including at least one of n-type GaN and n-type AlGaN; a second layer including Mg-containing p-type AlGaN; and a light emitting section provided between the first and second layers. The light emitting section includes barrier layers of Si-containing AlxGa1-x-yInyN (0≦x, 0≦y, x+y≦1), and a well layer provided between the barrier layers and made of GaInN or AlGaInN. The barrier layers have a nearest barrier layer nearest to the second layer among the barrier layers and a far barrier layer. The nearest barrier layer includes a first portion made of Si-containing AlxGa1-x-yInyN (0≦x, 0≦y, x+y≦1), and a second portion provided between the first portion and the second layer and made of AlxGa1-x-yInyN (0≦x, 0≦y, x+y≦1). The Si concentration in the second portion is lower than those in the first portion and in the far barrier layer.