A cleaning element to clean an object to be cleaned comprising: a fiber assembly formed by a plurality of fibers extending in a direction transverse to a longitudinal direction of the cleaning element, a nonwoven fabric laminate formed by a plurality of nonwoven fabric sheets, a bonded part (121,122,123) to bond the fiber assembly and the nonwoven fabric laminate which are overlaid one on the other, and an insert region which is defined by the plurality of nonwoven fabric sheets and the bonded part (121,122,123) and receives a holding element of a cleaning element holder, wherein the bonded part (121,122,123) has an outer bonded part which defines an outer side of the insert region in a direction transverse to the longitudinal direction of the cleaning element; characterized in that: the outer bonded part includes a plurality of bonded portions (121, 122,123) extending along the longitudinal direction of the cleaning element; the bonded portions (123a,123b,123c) are disposed in positions displaced from each other in a direction transverse to the longitudinal direction of the cleaning element; the bonded portions (123a,123b,123c) of the outer bonded part include a first bonding line disposed inward of a second bonding line in a direction transverse to the longitudinal direction of the cleaning element, the fiber length or amount of the fiber assembly extending outward from the outer bonded part in the direction transverse to the longitudinal direction of the cleaning element being larger in a region in which the first bonding line is formed than in a region in which the second bonding line is formed; and a third bonding line disposed inward of the second bonding line in the direction transverse to the longitudinal direction of the cleaning element, the fiber length or amount of the fiber assembly extending outward from the outer bonded part in the direction transverse to the longitudinal direction of the cleaning element being larger in the regions in which the first and third bonding lines (123c, 123a) are formed than in the region in which the second bonding line is formed. a fiber assembly formed by a plurality of fibers extending in a direction transverse to a longitudinal direction of the cleaning element, a nonwoven fabric laminate formed by a plurality of nonwoven fabric sheets, a bonded part (121,122,123) to bond the fiber assembly and the nonwoven fabric laminate which are overlaid one on the other, and an insert region which is defined by the plurality of nonwoven fabric sheets and the bonded part (121,122,123) and receives a holding element of a cleaning element holder, wherein the bonded part (121,122,123) has an outer bonded part which defines an outer side of the insert region in a direction transverse to the longitudinal direction of the cleaning element; characterized in that: the outer bonded part includes a plurality of bonded portions (121, 122,123) extending along the longitudinal direction of the cleaning element; the bonded portions (123a,123b,123c) are disposed in positions displaced from each other in a direction transverse to the longitudinal direction of the cleaning element; the bonded portions (123a,123b,123c) of the outer bonded part include a first bonding line disposed inward of a second bonding line in a direction transverse to the longitudinal direction of the cleaning element, the fiber length or amount of the fiber assembly extending outward from the outer bonded part in the direction transverse to the longitudinal direction of the cleaning element being larger in a region in which the first bonding line is formed than in a region in which the second bonding line is formed; and a third bonding line disposed inward of the second bonding line in the direction transverse to the longitudinal direction of the cleaning element, the fiber length or amount of the fiber assembly extending outward from the outer bonded part in the direction transverse to the longitudinal direction of the cleaning element being larger in the regions in which the first and third bonding lines (123c, 123a) are formed than in the region in which the second bonding line is formed. the outer bonded part includes a plurality of bonded portions (121, 122,123) extending along the longitudinal direction of the cleaning element; the bonded portions (123a,123b,123c) are disposed in positions displaced from each other in a direction transverse to the longitudinal direction of the cleaning element; the bonded portions (123a,123b,123c) of the outer bonded part include a first bonding line disposed inward of a second bonding line in a direction transverse to the longitudinal direction of the cleaning element, the fiber length or amount of the fiber assembly extending outward from the outer bonded part in the direction transverse to the longitudinal direction of the cleaning element being larger in a region in which the first bonding line is formed than in a region in which the second bonding line is formed; and a third bonding line disposed inward of the second bonding line in the direction transverse to the longitudinal direction of the cleaning element, the fiber length or amount of the fiber assembly extending outward from the outer bonded part in the direction transverse to the longitudinal direction of the cleaning element being larger in the regions in which the first and third bonding lines (123c, 123a) are formed than in the region in which the second bonding line is formed.