To reduce the capacity of a buffer in time division decoding when it is possible that the input of one of plural encoded audio signal sequences is tentativelly stopped.

This device decodes the encoded signal sequences of multiplexed (n) (n is an integer ≥2) systems in a time division manner and outputs the decoded signal sequences of the (n) systems. In this case, the device is provided with a time division control means 104 for controlling a decoding means 101 so as to decode the encoded signal sequences of the (n) systems in a time division manner by a frame unit which is the unit of decoding, a ring buffer 102 provided at least with the capacity of (2n-1=3) frames to be shared among the decoded signal sequences of the (n) systems and the time division control means 104 and a buffer input/output control means 103 for dynamically allocating the buffer capacity to the respective decoded signal sequences in cooperation when the input of the encoded signal sequence to be the reference of the time division decoding is tentatively stopped.