To evaluate the influence on sleep by mobility and comfort on a mattress, we estimated subjective sleep feelings and measured sleep quality by polysomnography. Ten healthy subjects (4 males, 6 females), aged 62-67, were recorded, sleeping in a laboratory for two nights at a week interval under two crossover designed conditions (EMC: a mattress easy to move and comfortable by first impressions, DMU: a mattress difficult to move and uncomfortable by first impressions). The percentage of wakefulness in the first half of sleep time was significantly increased at DMU. Subjective sleep feelings were better at EMC and subjective evaluations at the time of arising showed EMC was easier to move and more comfortable. These results suggest that mobility and comfort on a mattress is important for better sleep.