A solid-state imaging device comprising: a plurality of pixels each of which includes a photoelectric conversion unit that generates charges by photoelectric conversion; a first holding portion that holds charges transferred from the photoelectric conversion unit; a second holding portion that holds charges transferred from the first holding portion; and an amplifier unit that outputs a signal based on an amount of charges held by the second holding portion, wherein the photoelectric conversion unit includes a first semiconductor region of a first conductivity type provided in a semiconductor substrate and in contact with a surface of the semiconductor substrate, a second semiconductor region of a second conductivity type provided under the first semiconductor region and adapted to accumulate the generated charges, a third semiconductor region of the first conductivity type provided under the second semiconductor region, an impurity concentration of the third semiconductor region is set so that the entirety of the third semiconductor region is not depleted, and a fourth semiconductor region of the second conductivity type provided under the third semiconductor region, an impurity concentration of the fourth semiconductor region is set so that the fourth semiconductor region is depleted when charges are accumulated in the second semiconductor region, wherein the third semiconductor region has an opening in a region overlapping with the second semiconductor region in a plan view, and the second semiconductor region and the fourth semiconductor region are connected via the opening, wherein the fourth semiconductor region is provided extending under a sixth semiconductor region, wherein the first holding portion includes a fifth semiconductor region of the second conductivity type provided spaced apart from the second semiconductor region, and the sixth semiconductor region of the first conductivity type provided under the fifth semiconductor region at a depth at which the third semiconductor region is provided, and wherein the second semiconductor region and the fourth semiconductor region are connected to each other via the opening to form a continuous semiconductor region, such that the continuous semiconductor region having a lower potential than each of the third semiconductor region and the sixth semiconductor region is provided between the third semiconductor region and the sixth semiconductor region, characterized in that in a plan view, the opening is arranged within an area between a center part of the photoelectric conversion unit and the first holding portion. a plurality of pixels each of which includes a photoelectric conversion unit that generates charges by photoelectric conversion; a first holding portion that holds charges transferred from the photoelectric conversion unit; a second holding portion that holds charges transferred from the first holding portion; and an amplifier unit that outputs a signal based on an amount of charges held by the second holding portion, a first semiconductor region of a first conductivity type provided in a semiconductor substrate and in contact with a surface of the semiconductor substrate, a second semiconductor region of a second conductivity type provided under the first semiconductor region and adapted to accumulate the generated charges, a third semiconductor region of the first conductivity type provided under the second semiconductor region, an impurity concentration of the third semiconductor region is set so that the entirety of the third semiconductor region is not depleted, and a fourth semiconductor region of the second conductivity type provided under the third semiconductor region, an impurity concentration of the fourth semiconductor region is set so that the fourth semiconductor region is depleted when charges are accumulated in the second semiconductor region, wherein the third semiconductor region has an opening in a region overlapping with the second semiconductor region in a plan view, and the second semiconductor region and the fourth semiconductor region are connected via the opening, wherein the fourth semiconductor region is provided extending under a sixth semiconductor region, a fifth semiconductor region of the second conductivity type provided spaced apart from the second semiconductor region, and the sixth semiconductor region of the first conductivity type provided under the fifth semiconductor region at a depth at which the third semiconductor region is provided, and wherein the second semiconductor region and the fourth semiconductor region are connected to each other via the opening to form a continuous semiconductor region, such that the continuous semiconductor region having a lower potential than each of the third semiconductor region and the sixth semiconductor region is provided between the third semiconductor region and the sixth semiconductor region, characterized in that in a plan view, the opening is arranged within an area between a center part of the photoelectric conversion unit and the first holding portion.