To suppress reduction in thickness of a veneer single plate as far as possible in a dehydrator mechanically dehydrating contained moisture by passing the veneer single plate between a pair of rolls and compressing it in a thickness direction.

There is provided a dehydrator mechanically dehydrating contained moisture by passing a veneer single plate 4 between a pair of upper and lower rolls 1, 2 which are oppositely provided across an appropriate gap S and at least one of which is rotatably driven, and compressing it in a thickness direction. A metallic roll formed by dispersedly disposing appropriately shaped protrusions 3 on a peripheral surface of the roll is used for at least the upper roll 2 of the pair of rolls, and, in at least a sectional shape in a direction parallel to an axial direction of the upper roll 2 in the protrusions 3, at least for a cross sectional shape of a base end, a contour of at least either of the right side or left side with respect to the rotating direction of the upper roll 2 is formed into a flared arcuate shape.