An apparatus for controlling operation of an autonomously navigating utility vehicle equipped with a prime mover to travel about a working area delineated by a boundary wire in order to perform work autonomously, the apparatus comprising: a position detector configured to detect a position of the vehicle in the working area; an objective location identifying unit configured to identify a location of an objective in the working area; a route generating unit configured to generate a target return route for the vehicle to return from the position detected by the position detector to the objective whose location is identified by the objective location identifying unit, wherein the route generating unit selects, among a first set of radial lines imaginarily drawn on the working area to radiate from the position of the vehicle and a second set of radial lines imaginarily drawn on the working area to radiate from the location of the objective, a first radial line and a second radial line that result in shortest distance from the position of the vehicle to the location of the objective, wherein the route generating unit calculates multiple intersection points of the first set of radial lines and the second set of radial lines on the working area, selects a target intersection point (P1a) among the calculated intersection points such that the first radial line and the second radial line result in the shortest distance from the position of the vehicle to the objective when connected with each other via the target intersection point (P1a), and generates the target return route by the first radial line and the second radial line; and a travel controlling unit that controls operation of the prime mover to make the vehicle travel along the target return route generated by the route generating unit, characterized in that, when no intersection points between the first set of radial lines and the second set of radial lines are present in the working area, the route generating unit calculates multiple first intersection points where the first set of radial lines and the boundary wire intersect and second intersection points where the second set of radial lines and the boundary wire intersect, and among the first intersection points and the second intersection points, selects a first target intersection point (P11a) and a second target intersection point (P21a) connected to a boundary route segment (RTa) with no other intersection point (P11 or P21) present between the selected first target intersection point (P11a) and second target intersection point (P21a) such that the first radial line and the second radial line plus the boundary route segment (RTa) commonly result in shortest distance from the position of the vehicle to the objective. a position detector configured to detect a position of the vehicle in the working area; an objective location identifying unit configured to identify a location of an objective in the working area; a route generating unit configured to generate a target return route for the vehicle to return from the position detected by the position detector to the objective whose location is identified by the objective location identifying unit, wherein the route generating unit selects, among a first set of radial lines imaginarily drawn on the working area to radiate from the position of the vehicle and a second set of radial lines imaginarily drawn on the working area to radiate from the location of the objective, a first radial line and a second radial line that result in shortest distance from the position of the vehicle to the location of the objective, wherein the route generating unit calculates multiple intersection points of the first set of radial lines and the second set of radial lines on the working area, selects a target intersection point (P1a) among the calculated intersection points such that the first radial line and the second radial line result in the shortest distance from the position of the vehicle to the objective when connected with each other via the target intersection point (P1a), and generates the target return route by the first radial line and the second radial line; and a travel controlling unit that controls operation of the prime mover to make the vehicle travel along the target return route generated by the route generating unit, characterized in that, when no intersection points between the first set of radial lines and the second set of radial lines are present in the working area, the route generating unit calculates multiple first intersection points where the first set of radial lines and the boundary wire intersect and second intersection points where the second set of radial lines and the boundary wire intersect, and among the first intersection points and the second intersection points, selects a first target intersection point (P11a) and a second target intersection point (P21a) connected to a boundary route segment (RTa) with no other intersection point (P11 or P21) present between the selected first target intersection point (P11a) and second target intersection point (P21a) such that the first radial line and the second radial line plus the boundary route segment (RTa) commonly result in shortest distance from the position of the vehicle to the objective.