A three-dimensional full electromagnetic particle-in-cell (PIC ) code, TRISTAN (Tridimensional Stanford) code, has been parallelized using High Performance Fortran (HPF) as a RPM (Real Parallel Machine). In the parallelized HPF code, the simulation domain is decomposed in one-dimension, and both the particle and field data located in each domain that we call the sub-domain are distributed on each processor. Both the particle and field data on a sub-domain are needed by the neighbor sub-domains and thus communications between the sub-domains are inevitable. Our simulation results using HPF exhibit the promising applicability of the HPF communications to a large scale scientific computing such as solar wind-magnetosphere interactions.