An engine system includes: an engine including a plurality of combustion chambers generating driving torque by combustion of fuel; an exhaust gas purification apparatus installed at an exhaust line in which exhaust gas exhausted from the combustion chambers flows; a bypass line branched from the exhaust line at an upstream side of the exhaust gas purification apparatus and joining the exhaust line at a downstream side of the exhaust gas purification apparatus so that the exhaust gas flowing in the exhaust line bypasses the exhaust gas purification apparatus; and a bypass valve installed at the bypass line.