The larvae of Euphausia nana Brinton in Sagami Bay and Suruga Bay, Central Japan, are described and illustrated. The furcilia stage is separated into six stages on the basis of the form of the pleopods and the number of terminal telson spines. Furcilia I, no pleopod or non-setose pleopods and seven terminal telson spines. Furcilia II, nonsetose and setose pleopods and seven terminal telson spines. Furcilia III, five pairs of setose pleopods and seven terminal telson spines. Furcilia IV, five pairs of setose pleopods and five terminal telson spines. Furcilia V, five pairs of setose pleopods and three terminal telson spines. Furcilia VI, five pairs of setose pleopods and one terminal telson spine. Segmentation of the antennal endopod and mandible palp occurred at the furcilia V stage. The dominant forms of early furcilia larvae of E. nana differed during different seasons of the year. The total lengths of calyptopis III and furcilia I to VI larvae also showed seasonal changes; they were largest in May and smallest from September to December.