Understanding the rapidly expanding influences of short-form videos on cognition is critical. Previous studies have investigated the relationship between short-form video and several cognitive functions. However, few empirical studies have examined the effects of short-form video consumption on sustained attention. This study aimed to address these impacts through an online survey and a long-term field experiment. The online survey utilized a psychological test and found that an increased amount of short-form video consumption relates to poor sustained attention. The long-term field experiment clarified the directionality of the effect through long-term observation and sustained attention tests conducted at fixed intervals. We found that changing the duration of short-form video consumption does not significantly influence performance on most sustained attention tests. Our research constitutes a preliminary exploration that revealed the effects of short-form videos on sustained attention.