A backlight device (12) includes a light guide plate (14), and LEDs (17), and wiring portions (18c). The light guide plate (14) has a substantially circular outer shape and has fan-shaped areas (SA) defined by segment lines (SL) extending through a center (C) thereof. All the segment lines (SL) meet at the center (C). The LEDs (17) are arranged such that middle positions between LEDs (17) each located at an end in the circumferential direction in the respective sets of the LEDs (17) provided for the fan-shaped areas (SA) adjacent to each other in the circumferential direction coincides with the segment lines (SL). The wiring portions (18c) are equal or larger in number than the LEDs (17) included in each of the sets of LEDs (17) provided for the fan-shaped areas (SA) and are configured to supply electric power to the respective LEDs (17).