To provide a sterilizing device that air bubbles are prevented from being generated or remaining in a sterilizing treatment vessel part and uniform and stable sterilization by electric field is executed by attaining the equal electric field.

The sterilizing treatment vessel part 30 of the device is provided with a high voltage electrode 32 and two grounded electrodes 34 which are mutually planar in parallel and they are arranged by erection in a vertical direction. The treatment part 36 of a liquid matter 2 is formed between the electrodes 32 and 34 and the liquid matter 2 flows in an upward direction J through it. Insulating objects 38 for permitting the width W1 of the treatment part 36 to coincide with that of the electrode 32 are arranged in the both end parts of the part 36. Auxiliary electrodes 42 and 44 are respectively extended in the electrodes 32 and 34. The both end parts of the electrode 32 in the direction J have a streamline shape. The entrance part and the exit part of the liquid matter 2 are arranged at positions with a distance being larger than the one L1 between the electrodes 32 and 34 from the end part of the electrode 32.