The Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting a plan to construct a 1MW neutron source facility at the Tokai Research Establishment, JAERI, under the Japan Proton Accelerator Research Complex (J-PARC) Project. In the facility, 1 MW pulsed proton beam from a high-intensity proton accelerator will be injected into a mercury target in order to produce high-intensity pulse neutrons for use in the fields of life and material sciences. In order to realize such a high-power neutron source, the design activity of a cross flow type (CFT) mercury target and its peripheral devices has continued and the results is reflected in the ordering specifications of the facility construction. The arrangement of each component and their structure was optimized through experimental and analytical studies. In this paper, the present design of the mercury target components for 1MW spallation neutron source including the target vessel, a mercury circulation system, and a target trolley will be reported.