The invention provides a display device circuit board arranged on a display device and capable of realizing small size and high precision of installation, the display device with small size and high reliability, and an electronic device. The display device circuit board includes a flexible substrate having a base portion, a connector mounting portion disposed along a first direction from the baseportion, a light emitter mounting portion, and an arm portion connecting the base portion and the light emitter mounting portion; and a connector reinforcing plate arranged on one main surface of oneside of the connector mounting portion, in which a gap is interposed between the light emitter mounting portion and the connector mounting portion and between the arm portion and the connector mounting portion.