Ockham's view of time agrees with that of Aristotle (Phys. 218b 21- 219b 5) and Averroes (com. 98, 132 and 133), for whom time and movement always correspond and define one another. But the difference between Ockham and the above-mentioned philosophers was one of conception. Ockham considers time as nother facet of individual existence. Firstly, this work focuses on the determination of time reality and its definition. Secondly, It analyses the problem of the measurement of time: the circularity of time and the measurement of motion had been already noticed by Augustinus; the details of Ockham's argument show dependence on Confessions XI, 21, 24; and especially 26.