An exhaust purifying device mounted in a working vehicle includes: an exhaust passage through which an exhaust gas discharged from an engine flows; a throttle valve configured to change a passage area of the exhaust passage; an exhaust aftertreatment device disposed downstream of the throttle valve; and a valve controller configured to control an open degree of the throttle valve. The valve controller is configured to control the open degree of the throttle valve to be larger in a low load region below a predetermined load range and in a high load region exceeding the predetermined load range than in a medium load region that is the predetermined load range.