AbstractTwo new ideas are going to be applied for the fusion product measurement, on LHD. One is a neutron emission monitor, located at the torus center, which has such a high detection efficiency that good statistics can be expected even in experiments with a hydrogen plasma, and the other is an active charge exchange neutral particle analyzing system using a high energy neutral beam. This system will be used to measure fusion reactivity of a D-3He plasma, and to study the confinement of alpha particles in a helical system.