The present study aimed to determine the effects of cardboard beds on psychophysiological responses during night-time sleep. For this study, we included 16 healthy male participants who provided written informed consent. We established two experimental conditions: night-time sleep using cardboard beds and exercise mats. In both conditions, each participant ate dinner at 19:00, went to bed at 23:00, and woke up at 07:00. During night-time sleep in both conditions, we measured their heart rate (HR), blood pressure (BP), cardiac autonomic nervous system modulation (ANS), wrist activity to estimate sleep/wake, and subjective soundness of sleep. The number of wake episodes for 1 minute or longer was significantly higher in the cardboard bed condition than in the exercise mat condition. Consequently, the degree of subjective soundness of sleep was significantly higher in the cardboard bed condition than in the exercise mat condition. However, there were no significant differences in the HR, BP, ln HF, sleep efficiency, and sleeping time between the two conditions. These data suggest that using cardboard beds can improve the quality of sleep.