A control apparatus, a buck-boost power supply, and a control method that can control an output part comprising two primary switches which are N-type transistors without changing the switching frequency are provided. A control apparatus for a buck-boost power supply comprises: a pulse-width modulation (PWM) signal generator configured to generate a PWM signal having a pulse whose pulse width is based on an output voltage; a mode pulse signal generator configured to generate a mode pulse signal having a signal whose time period is based on at least one of an input voltage, a difference between an input voltage and the output voltage, and a difference between an input voltage and a voltage proportional to the output voltage; a first delayed signal generator configured to generate a first delayed signal having a pulse whose rising edge or falling edge is delayed for a first delay time from a rising edge or a falling edge of the pulse of the PWM signal; and an output controller configured to control an output part of the buck-boost power supply, based on the PWM signal, the mode pulse signal, and the first delayed signal, the output part comprising: two primary switches that are each an N-type transistor; a boost capacitor for driving the high-side switch of the primary switches; and two secondary switches that are each a transistor, wherein the output controller controls switching of the output part so that a first time period during which the high-side switch of the primary switches is off and the low-side switch of the primary switches is on is longer than or equal to the first delay time.