A cleaning tool, having a cleaning sheet and a holder for holding the cleaning sheet , wherein: the cleaning sheet is configured to extend in a longitudinal direction which is defined by a direction of insertion of the holder into the cleaning sheet , and in a transverse direction which is defined by a direction crossing the longitudinal direction, the holder has a holding part for holding the cleaning sheet , and a grip part which is connected to the holding part and designed to be held by a user, the cleaning sheet has a brush part capable of cleaning an object to be cleaned, a base , and an insertion part which is formed on the base and into which the holding part is inserted, the brush part includes a first brush part provided on one side of the base and a second brush part provided on the other side of the base , and the first brush part and the second brush part have a first region and a second region, respectively, which have different structures, wherein: the brush part comprises a fiber assembly , and the fiber assembly includes a first fiber assembly (100GF1) which forms the first brush part and a second fiber assembly (100GF2) which forms the second brush part , and the first fiber assembly (100GF1) and the second fiber assembly (100GF2) have different finenesses. the cleaning sheet is configured to extend in a longitudinal direction which is defined by a direction of insertion of the holder into the cleaning sheet , and in a transverse direction which is defined by a direction crossing the longitudinal direction, the holder has a holding part for holding the cleaning sheet , and a grip part which is connected to the holding part and designed to be held by a user, the cleaning sheet has a brush part capable of cleaning an object to be cleaned, a base , and an insertion part which is formed on the base and into which the holding part is inserted, the brush part includes a first brush part provided on one side of the base and a second brush part provided on the other side of the base , and the first brush part and the second brush part have a first region and a second region, respectively, which have different structures, wherein: the brush part comprises a fiber assembly , and the fiber assembly includes a first fiber assembly (100GF1) which forms the first brush part and a second fiber assembly (100GF2) which forms the second brush part , and the first fiber assembly (100GF1) and the second fiber assembly (100GF2) have different finenesses. the cleaning sheet has a brush part capable of cleaning an object to be cleaned, a base , and an insertion part which is formed on the base and into which the holding part is inserted, the brush part includes a first brush part provided on one side of the base and a second brush part provided on the other side of the base , and the first brush part and the second brush part have a first region and a second region, respectively, which have different structures, wherein: the brush part comprises a fiber assembly , and the fiber assembly includes a first fiber assembly (100GF1) which forms the first brush part and a second fiber assembly (100GF2) which forms the second brush part , and the first fiber assembly (100GF1) and the second fiber assembly (100GF2) have different finenesses. the brush part comprises a fiber assembly , and the fiber assembly includes a first fiber assembly (100GF1) which forms the first brush part and a second fiber assembly (100GF2) which forms the second brush part , and the first fiber assembly (100GF1) and the second fiber assembly (100GF2) have different finenesses. <EOS>