The coexistence of ferrimagnetic and ferroelectric orders in ϵ-Fe2O3 at room temperature makes it a promising multiferroic material. However, to investigate and enhance the ferroic functionalities, single crystals of this oxide must be synthesized. In this study, we successfully synthesized ϵ-Fe2O3-type single crystals, which exhibited room-temperature ferrimagnetism and spontaneous ferroelectric polarization simultaneously by codoping ϵ-Fe2O3 with Ga3+ and Sc3+. Using a floating zone method, large (diameter of ∼6 mm and length of ∼70 mm) and high-quality ϵ-ScxGa0.75-xFe1.25O3 (x = 0.05-0.15) single-crystal rods were obtained. The crystals exhibited strong magnetic anisotropy along the a-axis at 300 K. The magnetic transition temperature and the coercive field at 300 K decreased with increasing x. In addition, magnetic-field-induced modulation of the polarization was observed at a relatively high temperature (150 K) with a magnetoelectric coefficient of (2-5) × 10-11 S/m.