A resonant converter having a pre-conduction mechanism for realizing a wide output voltage range is provided. The resonant converter includes a first circuit and a second circuit. The first circuit includes a plurality of primary-side switches. The plurality of primary-side switches includes a first high-side switch, a second high-side switch, a first low-side switch and a second low-side switch. The second circuit includes a plurality of secondary-side switches. The plurality of secondary-side switches includes a third high-side switch, a fourth high-side switch, a third low-side switch and a fourth low-side switch. When the second low-side switch and the first low-side switch are turned on and a current time reaches a preset on time, the fourth high-side switch and the third low-side switch are turned on.