PURPOSE: An agricultural speed sprayer with improved mechanism of power transmission is provided to facilitate rapid and convenient change of a belt by enabling a user to simply unfasten the belt from a driven pulley. CONSTITUTION: An agricultural speed sprayer with improved mechanism of power transmission comprises an engine (4) which is installed on a vehicle to generate driving force for movement and operation； a first power transmission part (8) which is connected with the driving axle of the engine to transmit the power of the engine to a ventilation fan from the rear of the engine； a second power transmission part (14) which is connected with the driving axle of the engine to receive the driving force of the engine downwardly through a belt connected with the driving axle in the front of the engine； a third power transmission part (20) which is connected with a predetermined part to transmit the power received downwardly of the engine to the front of the vehicle； a gear device which is connected with a predetermined part of the third power transmission part to reduce speed with a reduction gear and to rotate a reversing gear in backward motion； a fourth power transmission part (22) which is connected with the output axle of the gear device and installed parallel on the bottom of the third power transmission part to transmit power to a front wheel and a rear wheel； a fifth power transmission part (100) which is connected with a predetermined part of the second power transmission part to transmit power received downwardly of the engine to the rear of the vehicle； and a high-pressure spray (130) which is operated by power transmitted from the fifth power transmission part.본 발명은 개선된 동력전달 매커니즘을 갖춘 스피드 스프레이어에 관한 것으로, 이물체가 비산되어 엔진이 파손되는 것을 방지하기 위해 단일의 엔진을 설치하면서도 방제기와 주행장치에 대해 엔진의 동력이 각각 선택적으로 제공할 수 있게 하며, 동력을 전달하는 벨트 교환시 간단하고 신속하게 교환 가능하게 이루어진 개선된 동력전달 매커니즘을 갖춘 스피드 스프레이어를 제공함에 그 목적이 있다.본 발명을 적용하면, 주동력 전달용인 벨트를 교체하고자 하는 경우에 조인트 볼트만을 간단하게 분해하면 유니버셜 조인트인 연결로드를 분해할 수 있
