A blanket (100A, 100B) includes a first button group (31) on the two left and right sides of the lower section of the blanket (100A, 100B). The first button group (31) includes an upper button group (31a) and a lower button group (31b), the upper and lower button groups (31a, 31b) including one or more buttons. An engagement part of the upper button group (31a) and an engagement part of the lower button group (31b) are provided on mutually different surfaces of the blanket (100A, 100B). The lower section of the blanket (100A, 100B) is folded back and the upper button group (31a) and the lower button group (31b) engage with each other, thereby maintaining the folded state of the blanket (100A, 100B).