Lynn Armstrong, who guarded West in the dock during her seven-week trial, is reportedly demanding £50,000.
She says she suffered a breakdown after listening to the horrific evidence during the trial at Winchester Crown Court in 1995.
Details of her and her husband Fred's reign of sexual violence, torture and killing were heard in the court.
Rose West received 10 life sentences for her part in the so-called House of Horrors saga.
'Prison service negligence'
Her husband committed suicide in prison before the trial for his part in the killings in Cromwell Street, Gloucester.
He was found hanging in his cell on New Year's Day 1995.
Mrs Armstrong's writ reportedly claims the prison authorities were negligent in disregarding her protests about being on duty with West for long periods.
She has since left her job for medical reasons.
A Prison Service spokesman said he had no details about the writ but said: "A prison officer is taking legal action against us."
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West case that haunts NHS staff
(15 Dec 98 | Health)
Woman traumatised by West case sues police
(04 Jun 98 | UK)
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