A data managing method, a memory controlling circuit unit, and a memory storage device are provided. The method includes: receiving a write command for writing a plurality of first data into a rewritable non-volatile memory module; when the plurality of first data are continuous data, writing the plurality of first data respectively into a plurality of first physical erasing units by using a single-page programming mode, and recording first management information corresponding to the plurality of first physical erasing units; and when the plurality of first data are not the continuous data, writing the plurality of first data respectively into a plurality of second physical erasing units by using the single-page programming mode.