PURPOSE: To provide a semiconductor memory device in which semiconductor can be easily buried in a trench, a leakage current can be reduced at the time of nonconducting, a refresh cycle can be extended and a soft error can be eliminated.

CONSTITUTION: A trench 53 is formed on a semiconductor substrate, a capacitor insulating film 54 is formed on an inner wall of the trench, polysilicon is buried in the trench, a storage node electrode 55 is formed, a capacitor is formed, an independent single crystalline silicon 56 is formed directly above the capacitor, a gate oxide film 57 and a gate electrode 58 are formed on the sidewall, and N+ type diffused layers 59, 60 are respectively formed on the upper and lower parts of the single crystalline silicon.