To provide a continuous casting method for molten metal in which a cast slab having good surface quality can stably be cast at a high speed.

A conductive coil 3 is vibrated in the casting direction and, high frequency current modulated by an effective value synchronously with the vibrating frequency of the conductive coil 3 is supplied into the conductive coil 3. The resonance frequency is measured at a specified phase of the high frequency current modulated by the effective value, and the supplying speed of the molten metal is adjusted with a molten metal supply control unit 18 so that te detected resonance frequency at the upper end position in the vibrating range of the conductive coil 3 becomes a preset value.