A neck cover (51) includes a flexible cover member (53) and a to-be-attached portion (52) which serves to attach the flexible cover member (53) to a head protecting body (3) of a full-face-type helmet (1). The flexible cover member (53) comprises a substantially plate-like flexible cushion member (56) and a flexible support member (57) which supports the flexible cushion member (56). The flexible cover member (53) is mainly made of a substantially plate-like foamed synthetic resin, a permeability of which measured by using a Frajour type method based on JIS L 1096 falls within a range of 0.1 to 10 cc/cm2·sec (preferably 0.2 to 5 cc/cm2·sec and more preferably 0.3 to 2 cc/cm2·sec).Therefore, a sound which is generated by a traveling wind as it is caught in a ventilator, stabilizer, or the like is effectively prevented from being heard as loud noise to a helmet wearer.