A straddled vehicle comprising: an engine which includes at least one combustion chamber and a crankshaft, wherein at least one throttle valve is provided for each of the at least one combustion chamber; an exhaust passage member configured to let pass exhaust gas exhausted from the at least one combustion chamber therethrough; at least one oxygen sensor (20, 25, 26) each of which includes a sensor element configured to detect oxygen concentration of the exhaust gas in the exhaust passage member and a heater configured to heat the sensor element; a controller configured to perform an oxygen sensor heater control with which electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) is controlled; and a power switch which is switchable to an on-state by a rider in order to supply electric power to the controller, the controller being configured to perform an idling stop/start control to automatically shift the engine from a driving state in which the crankshaft rotates to an idling stop state in which the crankshaft does not rotate while the power switch is in the on-state, and to return the engine from the idling stop state to the driving state when an operation related to a rider's intention to run is performed by the rider, and the controller being configured to perform a control in which the oxygen sensor heater control and the idling stop/start control are integrated, in such a way that (i) when the controller shifts the engine to the idling stop state while the power switch is in the on-state, the electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) is stopped irrespective of temperature of the sensor element, (ii) after the first operation related to a rider's intention to run is performed after the shift to the idling stop state, the electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) is restarted irrespective of the temperature of the sensor element, and (iii) after the shift to the idling stop state and until the first operation related to the rider's intention to run is performed after the shift to the idling stop state, return of the engine to the driving state and restart of the electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) are avoided. an engine which includes at least one combustion chamber and a crankshaft, wherein at least one throttle valve is provided for each of the at least one combustion chamber; an exhaust passage member configured to let pass exhaust gas exhausted from the at least one combustion chamber therethrough; at least one oxygen sensor (20, 25, 26) each of which includes a sensor element configured to detect oxygen concentration of the exhaust gas in the exhaust passage member and a heater configured to heat the sensor element; a controller configured to perform an oxygen sensor heater control with which electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) is controlled; and a power switch which is switchable to an on-state by a rider in order to supply electric power to the controller, the controller being configured to perform an idling stop/start control to automatically shift the engine from a driving state in which the crankshaft rotates to an idling stop state in which the crankshaft does not rotate while the power switch is in the on-state, and to return the engine from the idling stop state to the driving state when an operation related to a rider's intention to run is performed by the rider, and the controller being configured to perform a control in which the oxygen sensor heater control and the idling stop/start control are integrated, in such a way that (i) when the controller shifts the engine to the idling stop state while the power switch is in the on-state, the electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) is stopped irrespective of temperature of the sensor element, (ii) after the first operation related to a rider's intention to run is performed after the shift to the idling stop state, the electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) is restarted irrespective of the temperature of the sensor element, and (iii) after the shift to the idling stop state and until the first operation related to the rider's intention to run is performed after the shift to the idling stop state, return of the engine to the driving state and restart of the electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) are avoided. (i) when the controller shifts the engine to the idling stop state while the power switch is in the on-state, the electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) is stopped irrespective of temperature of the sensor element, (ii) after the first operation related to a rider's intention to run is performed after the shift to the idling stop state, the electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) is restarted irrespective of the temperature of the sensor element, and (iii) after the shift to the idling stop state and until the first operation related to the rider's intention to run is performed after the shift to the idling stop state, return of the engine to the driving state and restart of the electric power supply to the heater of the at least one oxygen sensor (20, 25, 26) are avoided.