By making use of the linear operator ⊖λ,n m, m ∈ (The symbol is abbreviated)={1,2,3,...} and λ, n ∈ (The symbol is abbreviated)0= (The symbol is abbreviated)∪{0} given by the authors, a class of analytic functions Sλ,n m(α,σ) (|α|< π/2, 0≤σ<1) is introduced. The object of the present paper is to obtain sharp upper bound for functional |a2a4−a23|.