<p>Provided is a technique for a power supply device which enables detection of a load supply current in a simplified configuration. The device enables a current detecting section (15) to detect the load supply current (i) from the voltage between the through electrodes (31) of a 3-terminal capacitor (30) which is interposed in a power supply path (40) between a power supply section (10) and a load (100). This allows the 3-terminal capacitor (30) operating as a filter for reducing ripple noise to serve also as a resistor for detecting the load supply current (i). Accordingly, this simple configuration allows for detecting the load supply current (i) without the need of a conventional resistor component for detecting the load supply current (i). This arrangement eliminates the need for ensuring a space for implementing the resistor component for detection of current, thus reducing the size of the power supply device (1). The elimination of the resistor component for detection of current can in turn contribute to a reduction in costs.</p>
