A power supply circuit (10) has a current control portion (5) that controls, at a predetermined level, the currents passed through LEDs (3) and (4); a current setting portion (6) that sets, in the current control portion (5), the level of currents to be passed through the LEDs (3) and (4); and a checking portion (7) that checks whether or not currents at the current level set by the current setting portion (6) can be passed through the LEDs (3) and (4). The checking portion (7), on recognizing a condition in which at least one of the LEDs (3) and (4) cannot be fed with a current at the level set by the current setting portion (6), feeds the current setting portion (6) with a signal indicating the condition; on receiving the signal, the current setting portion (6) changes the currently set current level to a current level at which currents can be passed through both the LEDs (3) and (4). This helps realize an LED driving power supply circuit that, despite having a small circuit scale, tolerates a wide range for the supplied voltage.