A sample preparation device comprising: a filter member (F) including a filter (F4) configured to separate cells being an analysis target from other components in a sample; a first receptacle and a second receptacle configured to be connected to each other via the filter (F4); a third receptacle capable of holding the sample therein; a communication hole (H22) formed in the first receptacle and configured to allow the sample to go into and out of the first receptacle ; a flow path configured to allow the third receptacle to be communicated with the communication hole (H22); a negative pressure section (P11) configured to apply a negative pressure into the second receptacle, thereby to move the sample in the third receptacle toward the filter (F4) via the flow path and the first receptacle , and thereby to move components other than the analysis target into the second receptacle via the filter (F4); a positive pressure section (P12) configured to apply a positive pressure from the second receptacle side to the filter (F4), wherein the cells being the analysis target are attached to the filter (F4) in the first receptacle side; and a rotating member (R) provided in the first receptacle and configured to rotate along a filtering face of the filter (F4), wherein the filter member (F) is provided with a cylindrical portion (F3) having a cylindrical inner side face (F31), the filter (F4) is located at a position inwardly displaced from an edge of the cylindrical portion (F3), and the rotating member (R) includes: an inner circular portion (R21) capable of being inserted into the cylindrical portion (F3), characterised in that the rotating member (R) also includes a restraining portion (R2) formed around the inner circular portion (R21) and configured to restrain the inner circular portion (R21) from coming into contact with the filter (F4). a filter member (F) including a filter (F4) configured to separate cells being an analysis target from other components in a sample; a first receptacle and a second receptacle configured to be connected to each other via the filter (F4); a third receptacle capable of holding the sample therein; a communication hole (H22) formed in the first receptacle and configured to allow the sample to go into and out of the first receptacle ; a flow path configured to allow the third receptacle to be communicated with the communication hole (H22); a negative pressure section (P11) configured to apply a negative pressure into the second receptacle, thereby to move the sample in the third receptacle toward the filter (F4) via the flow path and the first receptacle , and thereby to move components other than the analysis target into the second receptacle via the filter (F4); a positive pressure section (P12) configured to apply a positive pressure from the second receptacle side to the filter (F4), wherein the cells being the analysis target are attached to the filter (F4) in the first receptacle side; and a rotating member (R) provided in the first receptacle and configured to rotate along a filtering face of the filter (F4), wherein the filter member (F) is provided with a cylindrical portion (F3) having a cylindrical inner side face (F31), the filter (F4) is located at a position inwardly displaced from an edge of the cylindrical portion (F3), and the rotating member (R) includes: an inner circular portion (R21) capable of being inserted into the cylindrical portion (F3), characterised in that the rotating member (R) also includes a restraining portion (R2) formed around the inner circular portion (R21) and configured to restrain the inner circular portion (R21) from coming into contact with the filter (F4). <EOS>