To provide a fiber structure having good convenience, keeping the comfortableness in wearing, enabling easy continuous wearing, free from deterioration of the beautiful appearance in wearing and suitable for improving cold-sensitive constitution and skin diseases such as atopic dermatitis.

Amygdalin (vitamin B17) obtained by extraction of loquat seed and/or loquat leaf is encapsulated in microcapsules and attached to a fiber with a binder. The fiber structure may further contain capsicum tincture. Furthermore, a substance having far infrared effect, fine particles of moisture absorbing and releasing polymer, etc., may be attached to the structure. The product exhibits the effect to improve cold-sensitive constitution and skin diseases such as atopic dermatitis.