A flush toilet includes a toilet main body and a tank device, and the tank device includes a storage tank and a tank mounting member to which the storage tank is detachably attached. At a time of attachment of the storage tank to the tank mounting member, an attaching portion of the storage tank is engaged with an attachment-receiving portion of the tank mounting member by the storage tank being lowered onto a base of the tank mounting member from above. Then, when the storage tank is moved in a horizontal direction relative to the tank mounting member, the attaching portion of the storage tank is configured to be fixed to the attachment-receiving portion of the tank mounting member.