Accessory and helmet

The present invention provides an attachment capable of attaching a protective cover and a chin guard to a helmet main body, and a helmet provided with the attachment. The attachment (1) is attached to a helmet main body (3) having an opening (7) open to the front side, and the attachment (1) is provided with: an attachment main body (15) disposed in an edge region (A) defining the opening of the helmet main body; fixing structures (19, 69, 89) for fixing the accessory body to the helmet body; and a protective cover (35) and a jaw guard (39) which are provided to the attachment main body and are disposed in front of the wearer. 本发明提供附件和头盔，该附件能够将防护罩及下巴护件安装于头盔主体，该头盔设置有该附件。附件(1)安装于具有向前侧开放的开口(7)的头盔主体(3)，附件(1)具备：附件主体(15)，其配置于头盔主体的划定开口的缘部区域(A)；固定构造(19、69、89)，其用于将附件主体固定于头盔主体；及防护罩(35)和下巴护件(39)，它们设置于附件主体，配置于佩戴者的前方。