The present technology relates to a solid-state imaging element, an imaging device, and an electronic device that can improve transfer efficiency of a charge accumulation unit (MEM) and can increase the number of saturation electrons Qs. In a case where a charge voltage conversion unit (FD) is connected to a center of a charge accumulation unit (MEM) in each pixel and pixels are arrayed in an array, a column in which photoelectric conversion units (PD) are arrayed and a column including charge voltage conversion units (FD) and pixel transistors are arrayed in parallel. The present technology can be applied to a CMOS image sensor.