Multilayer nonwoven fabric and method of manufacturing the same

A multilayer nonwoven fabric, comprising:

• a first fiber layer having a first surface and a second surface opposite to the first surface in a thickness direction of the nonwoven fabric;
• and
• a second fiber layer arranged below the first fiber layer and having a third surface facing the first surface of the first fiber layer in the thickness direction,
• wherein
• a plurality of groove portions formed in the first and second fiber layers along a longitudinal direction are recessed in the thickness direction, and
• a plurality of raised ridge portions formed in the first and second fiber layers are projected in the thickness direction,
• the groove portions and the raised ridge portions are alternately arranged in a width direction orthogonal to the longitudinal direction,
• each of the raised ridge portions in the first and second fiber layers has opposite side parts each adjacent one of said groove portions, and
• a center part between the side parts;
• a basis weight of the raised ridge portions is greater than that of bottoms of the groove portions,
• in each of the raised ridge portions, the third surface of the second fiber layer is projected in a same direction as that in which the second surface of the first fiber layer is projected,
• a thickness of the first fiber layer is less than that of the second fiber layer in each of the raised ridge portions,
• the first fiber layer at the bottoms of the groove portions have more fibers oriented in the width direction than in the longitudinal direction,
• the side parts of each of the raised ridge portions arranged in the first fiber layer include fibers which have been moved from the adjacent groove portions to said side parts, and therefore, the side parts of each of said raised ridge portions in the first fiber layer have a basis weight greater than that at the center part of each of said raised ridge portions in the first fiber layer,
• the second fiber layer at the bottoms of the groove portions have more fibers oriented in the width direction than in the longitudinal direction,
• the side parts of each of the raised ridge portions arranged in the second fiber layer include fibers which have been moved from the adjacent groove portions to said side parts, and therefore, the side parts of each of said raised ridge portions in the second fiber layer have a basis weight greater than that at the center part of each of said raised ridge portions in the second fiber layer, and
• the side parts of each of the raised ridge portions have a ratio of the fibers oriented in the longitudinal direction per the fibers oriented in the width direction greater than that of the center part of each of the raised ridge portions.