The effects of implicit and explicit associative processes for false recognition were examined by manipulating exposure duration of studied items; 20 ms or 2000 ms. Participants studied lists of words that were high associates to a nonpresented word (critical lure) in either condition. After learning each list, they took a recognition test and remember/know judgements immediately (Experiment 1) or 1 minute later (Experiment 2). In Experiment 1, know responses for critical lures were more in the 20 ms than in the 2000 ms conditions, while remember responses for them were more in the 2000 ms condition. Implicit associative processes create familiarity of critical lures, and explicit associative processes create details of false memories. Comparing the results of Experiment 1 with those of Experiment 2, remember responses for critical lures were increased with the prolonged time only in the 20 ms condition. Characteristics of false memory made by implicit associative processes could be changed by prolonged time.