A brake system includes a brake activator which reduces, when a slipping condition of a right front wheel is detected based on a signal which is detected by a right detector, both braking forces on the right front wheel and a left front wheel to a lower level than a level of a braking force which is obtained as a result of operation of an input member and which reduces, when a slipping condition of the left front wheel is detected based on a signal which is detected by a left detector, both braking forces on the left front wheel and the right front wheel to a lower level than a level of a braking force which is obtained as a result of operation of the input member.