We conducted a questionnaire survey among 414 parents of 4- and 5-year-old children about the bed-time routine with respect to co-sleeping. By means of a text-mining method, we conducted a detailed analysis of free descriptions about the bed-time routine emerged: the children want to sleep in their favorite bedding items: the children go to sleep with a favorite stuffed animals close by where they sleep; the parents say the words of affection or read a picture book to the children; or the children obtain a sense of security through contact with their parent’s body. In terms of gender differences, it was evident that for boys, having an object such as a stuffed toy was as important as proximity to a parent; girls prefer eliminating anxiety or preparing for sleep than to spend a good time before they go to bed. Our results underlined the importance to the child’s sense of security in having the mother co-sleep throughout the night. We found that even if children co-sleep with the mother every evening, the children try to eliminate anxiety by thumb-sucking if they belive that the mother will leave the bed after they have fallen asleep.