A current measuring apparatus for measuring a power supply current received by an electronic device includes: a first current supplying unit for outputting a first current which is a part of the power supply current; a smoothing capacitor for smoothing the first current output by the first current supplying unit connected with one end thereof; a capacitor of device side for smoothing the power supply current, electrostatic capacity of the capacitor of device side being smaller than that of the smoothing capacitor and one end of the capacitor of device side being connected with the electronic device; a switch for making the first current flow from the smoothing capacitor to the capacitor of device side in case of being ON; a second current supplying unit for outputting a second current smaller than the first current to the capacitor of device side via a path parallel to the switch; and a power supply current acquiring unit for acquiring the power supply current on the basis of the second current output by the second current supplying unit.