Powder particles for forming a homogeneous green body having a sufficient strength and a process for producing a green body by using the powder particles. A green body is shaped by using powder particles of composite particles in which thermoplastic resin particles are scattered on surfaces of large particles in an amount within a predetermined volume ratio range with respect to the large particles, and loaded to form resin pools in contact point peripheral areas of adjoining ones of the large particles and form voids in areas other than the contact point peripheral areas when the thermoplastic resin particles are melted. A green body packed with the powder particles each having a small amount of the thermoplastic resin particles attached thereon is placed under a melting condition of the thermoplastic resin particles, the thermoplastic resin is melted and gathers around contact points (or proximal points) of the adjoining powder particles.