An image pickup device includes: a photodiode provided in a silicon substrate, and configured to generate electric charge corresponding to an amount of received light, by performing photoelectric conversion; and a transfer transistor provided at an epitaxial layer on the silicon substrate, and configured to transfer the electric charge generated in the photodiode, wherein the transfer transistor includes a gate electrode and a channel region, the gate electrode being embedded in the epitaxial layer, and the channel region surrounding the gate electrode, and the channel region has, in a thickness direction, a concentration gradient in which a curvature of a potential gradient is free from a mixture of plus and minus signs.