A button mounting device includes: a button mounting unit that comprises a first die holding the button main body and a second die holding the button mounting tool; an intermediate material formation unit that forms an intermediate material, which is to be interposed between the button main body and the cloth or between the button mounting tool and the cloth, by cutting a strip-shaped sheet material; and an intermediate material transfer unit that transfers the intermediate material formed by the intermediate material formation unit to the button mounting unit to supply the first die or the second die.