A dual-purpose probe applicable both to permittivity measurements and ablation of biological materials has been developed. For these purposes, a planar-type open-ended coaxial probe was used as an applicator due to its capabilities of broadband permittivity measurements and near-field ablation. In order to maintain highly efficient power transfer during ablation, an impedance matching network is designed. To verify the dual-purpose probe, the complex permittivity of several biological materials was measured, and a block of pork muscle was ablated. As a result, permittivity measurements were successfully achieved nearly up to 20 GHz, and the surface temperature of pork muscle was raised up to 70°C with only 31 dBm of incident power at 18 GHz.