The present disclosure provides a binary weighted current source and a digital-to-analog converter, which include: a driving voltage generating circuit, generating a driving voltage based on a preset current; a current dividing circuit, connected to an output terminal of the driving voltage generating circuit; a current steering circuit, connected to the current dividing circuit. The current dividing circuit divides the driving voltage through resistors in series, and drives each of a plurality of current output transistors to output a current in response to a voltage across the current output transistor. Currents output by the plurality of current output transistor are binary weighted currents, each two of the binary weighted currents have a binary relationship, and the binary weighted currents are produced by successive binary divisions of the preset current.