A reproduction time measuring circuit for measuring a reproduction time of digital data sampled at a predetermined frequency, the circuit comprises: a count circuit configured to count a clock of the predetermined frequency while the digital data is stored in an output buffer configured to output the digital data in accordance with the clock; and a reproduction time signal output circuit configured to output a reproduction time signal indicating that the digital data has been reproduced for a time corresponding to the predetermined value, when a count value of the clock output from the count circuit reaches a predetermined value.