A centrifugal smearing device comprising: a sealed rotating container that houses a chamber with a slide glass removably attached for holding a liquid sample and smearing cells in the liquid sample onto the slide glass with a centrifugal force; and a base housing the sealed rotating container and having rotational driving means for rotating the sealed rotating container, wherein said sealed rotating container includes: a main body being capable of housing said chamber, a lid configured to close an upper face opening portion of the main body, and a packing, wherein the lid includes a seal portion provided at an outer circumferential edge of said lid, being a site where the outside edge of the lid is a horizontal plane and projects outward, for sealing a space between the main body and an end face of the upper face opening portion of the main body, characterized in that: (i) the packing is mounted at the side of the lid at a leading end portion of the seal portion in such a manner to sandwich the seal portion of the lid; and (ii) a scattering protection wall is formed at an inside of the seal portion so as to protrude downward to hide the seal portion from inside, wherein the scattering protection wall slopes toward the outside and is formed in a ring-like shape making a circle at a lower portion of the lid so that, in use, any liquid scattered during the centrifugal smearing processing which comes into contact with the scattering protection wall drops obliquely downward along the scattering protection wall into a storage section of the main body so that the liquid does not scatter onto the seal portion. a sealed rotating container that houses a chamber with a slide glass removably attached for holding a liquid sample and smearing cells in the liquid sample onto the slide glass with a centrifugal force; and a base housing the sealed rotating container and having rotational driving means for rotating the sealed rotating container, wherein said sealed rotating container includes: a main body being capable of housing said chamber, a lid configured to close an upper face opening portion of the main body, and a packing, a main body being capable of housing said chamber, a lid configured to close an upper face opening portion of the main body, and a packing, wherein the lid includes a seal portion provided at an outer circumferential edge of said lid, being a site where the outside edge of the lid is a horizontal plane and projects outward, for sealing a space between the main body and an end face of the upper face opening portion of the main body, characterized in that: (i) the packing is mounted at the side of the lid at a leading end portion of the seal portion in such a manner to sandwich the seal portion of the lid; and (ii) a scattering protection wall is formed at an inside of the seal portion so as to protrude downward to hide the seal portion from inside, wherein the scattering protection wall slopes toward the outside and is formed in a ring-like shape making a circle at a lower portion of the lid so that, in use, any liquid scattered during the centrifugal smearing processing which comes into contact with the scattering protection wall drops obliquely downward along the scattering protection wall into a storage section of the main body so that the liquid does not scatter onto the seal portion. (i) the packing is mounted at the side of the lid at a leading end portion of the seal portion in such a manner to sandwich the seal portion of the lid; and (ii) a scattering protection wall is formed at an inside of the seal portion so as to protrude downward to hide the seal portion from inside, wherein the scattering protection wall slopes toward the outside and is formed in a ring-like shape making a circle at a lower portion of the lid so that, in use, any liquid scattered during the centrifugal smearing processing which comes into contact with the scattering protection wall drops obliquely downward along the scattering protection wall into a storage section of the main body so that the liquid does not scatter onto the seal portion.