To update management information without causing buffer overflow.

When updating file management information 63 on a recording medium 37, the amount of space in a stream buffer 71 within an imaging apparatus 1 is checked. If the stream buffer 71 does not have the amount of space in which stream data for a period required to update file management information 63 can be accumulated, update of the file management information 63 is reserved temporarily, and data in the stream buffer 71 is written out first in the recording medium 37 until the amount of space for the period required for update is secured. Thereafter, when the amount of space is secured, the file management information 63 is updated.