<p>Pill bugs (<i>Armadillidium vulgare</i>) demonstrate a behavior called turn repetition. For example, this behavior is seen when they repeat their path choice on successive trials of the T-mazes with long distance between T-junctions. However, sometimes, they stop after turning and change their direction. The function of this directional change has not been investigated for turn repetition. The present paper shows that pill bugs use directional changes to prevent them from turning in the different direction on two successive turns, a behavior called turn alternation. We examined the behavior of 20 pill bugs that each completed 49 successive combinations of L-corner and T-junction trials in an experimental pathway with long distance between the corner and the junction. Directional changes appeared more frequently when they began turn alternations than when they did turn repetitions. These results suggest that pill bugs have an inherent mechanism that acts to maintain turn repetition behavior.</p>