Shirehall Plain Antiques Centre reported to Norfolk Constabulary that £2000 worth of jewellery was taken on the afternoon on January 2.
After viewing CCTV the centre believes a man stole keys and accessed a cabinet and stole a number of items including brooches, rings and bracelets.
Anyone with information should contact Norfolk Constabulary quoting crime reference number 36/846/23 or contact Crimestoppers anonymously on 0800 555 111.