Proposed is a hybrid rocket engine using an electric motor-driven oxidizer pump, the hybrid rocket engine including: an oxidizer tank configured to store the oxidizer; an oxidizer pump configured to pressurize the oxidizer by being connected to the oxidizer tank through a first oxidizer supply line; a drive unit including an electric motor configured to drive the oxidizer pump and a battery configured to supply power to the electric motor; an auxiliary oxidizer line configured to guide the oxidizer from the oxidizer tank to the electric motor to cool the electric motor; an oxidizer recirculation line configured to recharge oxidizer vapor, generated through heat exchange between the electric motor and the oxidizer, to the oxidizer tank, thereby pressurizing an inner side of the oxidizer tank; and a combustion chamber configured to combust the oxidizer and fuel by being connected to the oxidizer pump through a second oxidizer supply line.