To perform operation check self-diagnosis of a digital terrestrial television broadcasting reception function of a multifunctional mobile communication terminal in any place without requiring addition of a special additional circuit component, or the like. When performing operation check self-diagnosis of a DTV reception unit 4, a first transmission signal of a GSM transmission/reception circuit 2 and a second transmission signal of a WLAN communication unit 3 are mixed using the non-linear characteristic of the LNA 41 of the DTV reception unit 4 while using transmission outputs of the GSM transmission/reception circuit 2 and WLAN communication unit 3. Due to the mixture, a difference signal having a frequency that is the difference between both the transmission signals in the reception frequency band of the DTV reception unit 4 is generated. On the basis of the difference signal, operation check self-diagnosis of the DTV reception unit 4 is performed.