A liquid component collecting device capable of more easily collecting a liquid compon ent. A liquid component collecting device (100) is provided with: a flexible cylindrical li quid component storage container (21) having an opening at one end thereof； a cylindr ical first housing container (22) for housing the liquid component storage container (21) and having an opening at one end thereof； and a first cap (23) connected to the ope ning in the liquid component storage container (21) and fitted to the opening in the firs t housing container (22). A pressure regulating space (26) independent of the internal space of the liquid component storage container (21) is formed between the outer sid e of the liquid component storage container (21) and the inner side of the first housin g container (22). The first cap (23) is provided with a liquid component inlet channel (27) for introducing blood into the liquid component storage container (21), a first com munication channel (28) communicating with the internal space of the liquid component storage container (21), and a second communication channel (29) communicating with the pressure regulating space (26).
