Mercury dispensers (10; 20) having a highly reduced particle loss and containing a mixture of powders of a mercury releasing compound and of a plastic metal or alloy and optionally of a getter material are described. A mercury dispensing device (10:20) has a filiform cross-section, obtained by cutting a manufactured product having the same cross-section but a higher length, and comprises a metal container (11;21) and a mixture (12;22) of powders, comprised of at least one material suitable for releasing mercury by heating and a metal or a metal alloy, said mixture being arranged inside the container. Said metal or metal alloy has a Vickers hardness lower than 130 HV, its weight percentage is lower than the 10% of the total weight of the powders mixture and the size of the powders of said metal or alloy are not bigger than the size of the other powders of the mixture.