A work vehicle having a pair of wheels (1, 2), comprising: a pair of brake operation devices (16R, 16L) each of which is configured to independently brake a corresponding wheel constituting the pair of wheels (1, 2); a coupling member movable between a coupling position and a releasing position, the coupling member being configured to connect together the pair of brake operation devices (16R, 16L) at the coupling position, and allow the pair brake operation devices (16R, 16L) to move independent of one another at the releasing position; a detector configured to detect whether the coupling member is in the coupling position or the releasing position; a speed controller (17, 44) configured to control a travel speed of the work vehicle; and a controller configured to communicate with the speed controller (17, 44) and configured to implement each of a first mode and a second mode; characterized in that in the first mode, the controller is configured to control the travel speed of the work vehicle so as to be consistent with a travel speed to be set by the speed controller (17, 44); in the second mode, the controller is configured to control the travel speed of the work vehicle so as to be lower than a travel speed to be set by the speed controller (17, 44); during vehicle travel in the first mode, the controller is configured to switch the first mode to the second mode when either: the detector detects that the coupling member positions at the releasing position, or the detector does not detect that the coupling member positions at the coupling position; and during vehicle travel in the second mode, the controller is configured to switch the second mode to the first mode when: the detector detects that the coupling member positions at the coupling position, and the controller determines that a releasing movement is performed by the speed controller (17, 44). a pair of brake operation devices (16R, 16L) each of which is configured to independently brake a corresponding wheel constituting the pair of wheels (1, 2); a coupling member movable between a coupling position and a releasing position, the coupling member being configured to connect together the pair of brake operation devices (16R, 16L) at the coupling position, and allow the pair brake operation devices (16R, 16L) to move independent of one another at the releasing position; a detector configured to detect whether the coupling member is in the coupling position or the releasing position; a speed controller (17, 44) configured to control a travel speed of the work vehicle; and a controller configured to communicate with the speed controller (17, 44) and configured to implement each of a first mode and a second mode; characterized in that in the first mode, the controller is configured to control the travel speed of the work vehicle so as to be consistent with a travel speed to be set by the speed controller (17, 44); in the second mode, the controller is configured to control the travel speed of the work vehicle so as to be lower than a travel speed to be set by the speed controller (17, 44); during vehicle travel in the first mode, the controller is configured to switch the first mode to the second mode when either: the detector detects that the coupling member positions at the releasing position, or the detector does not detect that the coupling member positions at the coupling position; and the detector detects that the coupling member positions at the releasing position, or the detector does not detect that the coupling member positions at the coupling position; and during vehicle travel in the second mode, the controller is configured to switch the second mode to the first mode when: the detector detects that the coupling member positions at the coupling position, and the detector detects that the coupling member positions at the coupling position, and the controller determines that a releasing movement is performed by the speed controller (17, 44).