Almost £25,000 has been spent on installing security measures at the homes of four judges, a Freedom of Information request has revealed.
Ministry of Justice figures show £20,918.74 was spent on safety improvements at one judge's house in 2014/15, the Press Association found.
Security at the homes of three judges was upgraded the following year, at a cost of £3,393.93.
A survey of judges found 51% feared for their safety while in court.
The Judicial Attitude Survey, which is released every two years, also found that 48% of female judges and 35% of male judges feared for their safety out of court.
The figures were released after a number of High Court and Supreme Court judges faced criticism when they ruled that Parliament must get a vote on the triggering of Article 50 to leave the EU.
One family and civil court judge told the Press Association that death threats and threats of hostage-taking and physical assault had become common.
The woman, who wished to remain anonymous, said a man who had his children taken away from him threatened to kill her and attempted to smuggle a knife into court.
She said the threats were so severe that police went to her home and spoke to neighbours to ensure she had a safety plan in place.
"The level of threats is getting worse. Incidents are common and the authorities are not even recording them," the judge said.
She added that judges were being routinely left in small rooms with both the accuser and the defendant without security or court clerks.
Almost a quarter of the most senior judges in England and Wales expressed concerns over safety online on websites like Facebook and Twitter.
Co-director of the UCL Judicial Institute, Prof Cheryl Thomas, said government cuts in legal aid had increased the number of people who were not represented by a lawyer.
"So as we have more and more people who need to go to court to resolve difficult, stressful, emotional family breakdown issues, who may not have access to lawyers to represent them, you have warring parties fighting it out in court," she added.
"And that places much greater security concerns on judges in court."