An asynchronous sampling frequency conversion device includes: a storage unit configured to store input digital signals; a data specifying unit configured to specify first data and second data based on a ratio of a sampling frequency of the input digital signal to a sampling frequency of an output digital signal, the first data being sampled at a sampling timing immediately before an ith (where i is a natural number) sampling timing of the output digital signal among the input digital signals stored in the storage unit, the second data being sampled at the sampling timing immediately after the ith sampling timing of the output digital signal; and an output data value calculator configured to calculate a value of ith data of the output digital signal based on the first data and the second data specified by the data specifying unit and the ratio.