Treatment apparatus

A treatment apparatus comprising:

• a vessel made of a microwave-reflecting material, and having a first end and a window or an opening portion for emitting microwaves into the vessel;
• a first filter located so as to partition the vessel, and configured to separate solids that are to be separated, from contents held in the vessel;
• and
• a first reflecting member located closer to the first end than a position of the opening portion is and so as to partition the vessel, the first reflective member partitioning a space in the vessel to suppress microwave irradiation by reflecting microwave to the opposite side of the first end with respect to the first filter, and configured to allow at least one of the contents having passed through the first filter to pass through the first reflecting member or allow the at least one of the contents having passed through the first reflecting member to pass through the first filter, and to reflect the microwaves,
• wherein the first reflecting member has one or more holes or opening portions through which the at least one of contents pass, wherein a diameter of each hole or opening portion is smaller than a half-wavelength of the microwaves.