We show that there exist double-charge solitons in a one-dimensional mesoscopic-junction array-in which-there are two excess electrons respectively on two different islands. The prominent feature of a double-charge soliton is its potential peak splitting into double peaks. The two peak values are not equal generally. The dependences of the peak potentials and threshold voltage of a double-charge soliton on the structure parameters of the tunnel junction array are also discussed. We also propose an equivalent single-charge soliton-description for a double-charge soliton.