A semiconductor device with flash memory includes; a log type determining unit configured to select log type from among a plurality of log types with respect to a log block storing program data requested to be programmed in the flash memory and generate a control signal indicating information indicating the selected log type, and a plurality of log units configured to store program data in the log block having a corresponding log type in response to the control signal, wherein the log type determining unit converts a first type log block formed by a first log type and included in a first type log unit from among the plurality of log units into second type log block formed by a second log type and converts the log block included in a second type log unit from among the plurality of log units into the first type log blocks, the first log type being different from the second log type.