The installation for manufacturing objects such as receptacles by thermoforming pellets of thermoplastic material includes conveyor means for conveying the pellets through the various stations in the installation, said stations including a heating station and a thermoforming station. The conveyor means comprise conveyor elements (46) defining cells (48) which are open upwards and downwards, and each of which is suitable for containing one pellet (12) while the entire top and bottom faces of the pellet remain unobstructed, means for depositing the pellets in the cells, drive means for driving the conveyor elements through the heating station, and transfer means (20) for transferring the heated pellets to the thermoforming station. The heating station includes bottom heater means (52) that co-operate with a support for the pellets while said conveyor elements are being driven through the heating station.