PURPOSE: To prevent picture quality from being degraded by preventing error correction from being performed to regenerative data beyond correcting ability, and interpolating those regenerative data.

CONSTITUTION: An in-code flag Flag outputted from an in-code decoder 4 is counted by a DOS threshold value controller 6, the threshold value of a drop-out signal from a DOS generator 5 is changed based on the result, the wirte of regenerative data into a memory 8 is inhibited by a drop-out signal DOS set based on this threshold value, and interpolation processing is performed to the regenerative data that write is inhibited. Thus, even the regenerative data beyond the correcting ability can be surely interpolated as well.