A generation control apparatus for vehicles is provided, in which a drastic change in the drive torque of a generator, which occurs with the cancellation of gradual excitation immediately after starting an internal combustion engine, can be suppressed to prevent stoppage of the internal combustion engine. The generation control apparatus includes an engine-start detection circuit, a gradual excitation circuit, a comparator for gradual-excitation cancellation, and a masking circuit for gradual-excitation cancellation. After detecting an engine start by the engine-start detection circuit, an instruction for gradual-excitation cancellation is released during an initial gradual excitation performed by a gradual excitation circuit, based on an output from the masking circuit for gradual-excitation cancellation. The drastic change in the drive torque occurring with the cancellation of the gradual excitation immediately after the engine start, can thus be suppressed, thereby preventing the engine stop.