PURPOSE: To make manufacturing equipment suitable for production of a small number of units as well, by enabling the injection and setting of synthetic resin in a high voltage transformer in a batch manner similar to a continuous manner.

CONSTITUTION: A fly-back transformer conveyed in from an assembly line 35 is transferred onto a turntable 22 in a vacuum injection vessel 7a, 7b by a throw-in conveyor 10. Mixed synthetic resin is injected from nozzles 8a, 8b. The injected resin is removed of bubbles by vacuum while the main and the setting agents of the preceding resin are injected. The transformer 1, into which the synthetic resin is already injected and which is already removed of bubbles, is thrown into a setting furnace 11aW11j by the conveyor 10. After a prescribed number of transformers are thrown into the furnace, the synthetic resin is set in a batch-type temperature distribution manner. After that, the transformers 1 are picked out from an outlet port onto a product conveyor 12 and conveyed back to the assembly line 35.