A sampling frequency conversion apparatus having sampling frequency conversion circuits for a plurality of channels includes a detector detecting phase information of digital signals inputted to the conversion circuit for each channel, and an input section inputting setting information for the conversion circuits for two or more channels to be phase-synchronized. The apparatus further includes a phase information supplier supplying the phase information for the conversion circuit for a specific channel designated by the setting information inputted into the input section to the conversion circuits for the remaining channels of those for two or more channels other than the conversion circuit for the specific channel, and a sampling frequency converter performing sampling frequency conversion on the phase information of the conversion circuits for the remaining channels in synchronization with the phase information for the specific channel supplied from the phase information supplier.