An engine having an output shaft extending in a specific direction, and an exhaust system comprising: an exhaust passage through which exhaust gas discharged from the engine circulates or passes; a turbocharger having a turbine housing, the turbine housing being formed therein with a passage through which exhaust gas passes and configured to accommodate a turbine wheel being driven by exhaust gas; and a first purifying part and a second purifying part configured to purify exhaust gas, wherein the exhaust passage includes: a first passage part connected to a downstream end of the turbine housing; a second passage part having the first purifying part therein and connected to a downstream end of the first passage part; and a third passage part (50, 60) having the second purifying part therein and connected to a downstream end of the second passage part, wherein the first passage part extends to one side in the specific direction from the turbine housing, wherein the third passage part (50, 60) extends in the specific direction below the turbine housing, wherein the second passage part extends upward from an end part of the third passage part (50, 60) at the one side in the specific direction, wherein a center axis of the second passage part inclines so that an upper end thereof is located on the one side in the specific direction of a lower end thereof or shifted to the one side in the specific direction from the lower end thereof, and wherein the first passage part has in an upper surface thereof an inclined part inclining so that a portion of the inclined part at the one side in the specific direction is located below a portion of the inclined part at the other side in the specific direction, characterized in that an oxygen sensor configured to detect a property of exhaust gas is attached to the inclined part, and a height of an upper end of the oxygen sensor is lowered, compared with a case where the upper surface of the first exhaust pipe extends linearly in the specific direction. an exhaust passage through which exhaust gas discharged from the engine circulates or passes; a turbocharger having a turbine housing, the turbine housing being formed therein with a passage through which exhaust gas passes and configured to accommodate a turbine wheel being driven by exhaust gas; and a first purifying part and a second purifying part configured to purify exhaust gas, wherein the exhaust passage includes: a first passage part connected to a downstream end of the turbine housing; a second passage part having the first purifying part therein and connected to a downstream end of the first passage part; and a third passage part (50, 60) having the second purifying part therein and connected to a downstream end of the second passage part, a first passage part connected to a downstream end of the turbine housing; a second passage part having the first purifying part therein and connected to a downstream end of the first passage part; and a third passage part (50, 60) having the second purifying part therein and connected to a downstream end of the second passage part, wherein the first passage part extends to one side in the specific direction from the turbine housing, wherein the third passage part (50, 60) extends in the specific direction below the turbine housing, wherein the second passage part extends upward from an end part of the third passage part (50, 60) at the one side in the specific direction, wherein a center axis of the second passage part inclines so that an upper end thereof is located on the one side in the specific direction of a lower end thereof or shifted to the one side in the specific direction from the lower end thereof, and wherein the first passage part has in an upper surface thereof an inclined part inclining so that a portion of the inclined part at the one side in the specific direction is located below a portion of the inclined part at the other side in the specific direction, characterized in that an oxygen sensor configured to detect a property of exhaust gas is attached to the inclined part, and a height of an upper end of the oxygen sensor is lowered, compared with a case where the upper surface of the first exhaust pipe extends linearly in the specific direction.