Non-dried allulose crystals are dried in a temperature treating step (b) in a drying apparatus at a temperature of about 25° C. to about 70° C., and in a conditioning step (c). The temperature treating step (b) may be carried out (b1) at atmospheric pressure and a residence time of about 5 minutes to about 5 hours. The temperature treating step (b) may be carried out (b2) under reduced pressure and constant temperature and a residence time from about 40 minutes to about 5 hours. The conditioning step (c) may be carried out (c1) over a period of about 30 minutes to 7 hours at a temperature from about 40° C. to about 70° C. The conditioning step (c) may be carried out (c2) over a period of about 15 minutes to about 90 hours at about 30 to about 60% relative humidity, and a temperature of about 25 to about 40° C.