Provided is a manufacturing method of ferromolybdenum from molybdenite concentrate, and more particularly, a manufacturing method of ferromolybdenum with copper content of 0.5% or less from molybdenite with high copper content without carrying out a separate copper removing process by putting molybdenite, aluminum metal and iron metal, in a heating furnace and reacting them at high temperature to manufacture the ferro molybdenum at the lower portion thereof, forming a slag using aluminum sulfide and iron sulfide as the main components at the upper portion thereof, and putting most of the copper (80 to 95%) existing in the molybdenite in a slag layer. The exemplary embodiment can shorten a process as compared to a metallothermic reduction (Thermit) method of the related art and reduce the consumption of a reducing agent, i.e., aluminum.