Fibre-reinforced-plastic ( FRP) cryostats have been developed for vari
ous cryogenic fields, such as superconducting magnets and cryogenic el
ectronics. The FRP cryostats ought to be used as liquid-helium contain
ers for the operation of a.c. and/or pulse superconducting magnets bec
ause the eddy-current losses induced in the metallic cryostats would b
e too large to operate the magnets stably. They are also needed for SQ
UID operation because the metallic cryostats disturb the weak magnetic
signals that are to be detected by the SOUID system. The material pro
blems and possible answers are summarized. The construction of FRP cry
ostats is demonstrated. Recently developed FRP cryostats for practical
applications in Japan are reviewed.