According to one embodiment, a solid-state imaging device is provided. The solid-state imaging device includes a photoelectric conversion element, a floating diffusion, and an amplifying transistor. The photoelectric conversion element photoelectrically convert incident light into electric charges with an amount corresponding to an amount of the incident light, and accumulates the electric charges. The floating diffusion accumulates the electric charges read out from the photoelectric conversion element. The amplifying transistor includes a gate electrode connected to the floating diffusion, and outputs a signal based on the amount of the electric charges accumulated in the floating diffusion. The amplifying transistor includes a first concentration region disposed in at least a part of the maximum region of the depletion layer and a second concentration region disposed at a deeper position than the first concentration region, and has higher impurity concentration than that of the first concentration region.