Adjacent interference is reliably detected in an FM tuner. A receiving field strength judgment circuit (102) compares a reception field strength signal SM-DC input from an S-meter circuit (92) and a reference voltage Vref2, and outputs a receiving strength judgment signal SRE. An SD band judgment circuit (104) uses a window comparator to determine, based on an f-V conversion characteristic of a detection output SDET, whether or not a voltage ΔV generated based on SDET is within a voltage range corresponding to a narrow band WN, and whether or not the voltage ΔV is within a voltage range corresponding to a wide band WW; and outputs determination signals SBD-N, SBD-W corresponding respectively to WN, WW. An SD circuit (106) performs a station detection based on SRE and SBD-N, and determines the presence or absence of adjacent interference based on, e.g., SBD-N and SBD-W.