[en] We report the results of a search for pair production of doubly charged Higgs bosons via pp→H⁺⁺H^--X→μ⁺μ⁺μ^-μ^-X at √(s)=1.96 TeV. We use a data set corresponding to an integrated luminosity of 1.1 fb^-1 collected from 2002 to 2006 by the D0 detector at the Fermilab Tevatron Collider. In the absence of an excess above the standard model background, lower mass limits of M(H_L^±±)>150 GeV/c² and M(H_R^±±)>127 GeV/c² at 95% C.L. are set, respectively, for left-handed and right-handed doubly charged Higgs bosons assuming a 100% branching ratio into muons