A parking lock mechanism used when a working vehicle is parked, the working vehicle comprising: a step part for locking, which is disposed at a front side of a brake step surface part of a brake pedal mechanism; and a lock unit which is connected to the step part for locking and which locks the brake pedal mechanism at a braking position thereof by the step part for locking being stepped on characterized in that the brake pedal mechanism, a forward pedal step surface part of a forward pedal mechanism configurated in order to move the working vehicle forward, and a backward pedal step surface part of a backward pedal mechanism configurated in order to move the working vehicle backward are disposed on one of a left side floor and a right side floor of a floor with reference to a center position of the floor, the forward pedal step surface part the forward pedal mechanism and the backward pedal step surface part the backward pedal mechanism are arranged in parallel and in a left-right direction, the brake step surface part is located in the front side of a step surface part of the forward pedal mechanism and the step surface part of the backward pedal mechanism, and a pedal lever main body of the brake pedal mechanism is formed to curve with swelling out in a front direction, the step part for locking is disposed adjacent to a front side edge among peripheral edges of the brake step surface part on a basis of a direction of movement of the working vehicle, the lock unit has an engagement part which engages with an engaged part, and a linkage mechanism (31, 33, 35) which connects the engagement part and the step part for locking; and the step part for locking, the engagement part and the linkage mechanism (31, 33, 35) are held at the pedal lever disposed below the brake step surface part, the engaged part is disposed on a frame, which is located below the floor, of a main body of the working vehicle. a step part for locking, which is disposed at a front side of a brake step surface part of a brake pedal mechanism; and a lock unit which is connected to the step part for locking and which locks the brake pedal mechanism at a braking position thereof by the step part for locking being stepped on characterized in that the brake pedal mechanism, a forward pedal step surface part of a forward pedal mechanism configurated in order to move the working vehicle forward, and a backward pedal step surface part of a backward pedal mechanism configurated in order to move the working vehicle backward are disposed on one of a left side floor and a right side floor of a floor with reference to a center position of the floor, the forward pedal step surface part the forward pedal mechanism and the backward pedal step surface part the backward pedal mechanism are arranged in parallel and in a left-right direction, the brake step surface part is located in the front side of a step surface part of the forward pedal mechanism and the step surface part of the backward pedal mechanism, and a pedal lever main body of the brake pedal mechanism is formed to curve with swelling out in a front direction, the step part for locking is disposed adjacent to a front side edge among peripheral edges of the brake step surface part on a basis of a direction of movement of the working vehicle, the lock unit has an engagement part which engages with an engaged part, and a linkage mechanism (31, 33, 35) which connects the engagement part and the step part for locking; and the step part for locking, the engagement part and the linkage mechanism (31, 33, 35) are held at the pedal lever disposed below the brake step surface part, the engaged part is disposed on a frame, which is located below the floor, of a main body of the working vehicle.