An extraction cassette (C) for extracting nucleic acid from a mixed liquid including a sample , comprising: a liquid receiving module for receiving the sample and alcohol and for mixing the sample with the alcohol to generate the mixed liquid ; and an extraction module for capturing the nucleic acid from the mixed liquid ; wherein the liquid receiving module communicates with the extraction module , and the liquid receiving module comprises a receiving module body having a first side , a second side opposite to the first side and a sample feeding hole formed on the first side ; wherein the receiving module body comprises: a sample compartment formed on the receiving module body and configured to receive the sample , wherein the sample compartment communicates with the sample feeding hole , and an alcohol compartment , formed on the receiving module body and configured to receive the alcohol , wherein the alcohol compartment communicates with the first sample compartment via a first path ; characterized in that the liquid receiving module further comprises a sealing member adapted to seal the sample feeding hole , wherein the sample compartment comprises a first sample compartment connection hole and a second sample compartment connection hole for connecting to the extraction module , the first sample compartment connection hole nears the first side relative to the second side , the alcohol compartment comprises an alcohol compartment connection hole that nears the second side relative to the first side , the first path connects the alcohol compartment connection hole to the first sample compartment connection hole for transferring the alcohol from the alcohol compartment to the sample compartment , and at least one portion of the first path is located between the alcohol compartment and the second side . a liquid receiving module for receiving the sample and alcohol and for mixing the sample with the alcohol to generate the mixed liquid ; and an extraction module for capturing the nucleic acid from the mixed liquid ; wherein the liquid receiving module communicates with the extraction module , and the liquid receiving module comprises a receiving module body having a first side , a second side opposite to the first side and a sample feeding hole formed on the first side ; wherein the receiving module body comprises: a sample compartment formed on the receiving module body and configured to receive the sample , wherein the sample compartment communicates with the sample feeding hole , and an alcohol compartment , formed on the receiving module body and configured to receive the alcohol , wherein a sample compartment formed on the receiving module body and configured to receive the sample , wherein the sample compartment communicates with the sample feeding hole , and an alcohol compartment , formed on the receiving module body and configured to receive the alcohol , wherein the alcohol compartment communicates with the first sample compartment via a first path ; characterized in that the liquid receiving module further comprises a sealing member adapted to seal the sample feeding hole , wherein the sample compartment comprises a first sample compartment connection hole and a second sample compartment connection hole for connecting to the extraction module , the first sample compartment connection hole nears the first side relative to the second side , the alcohol compartment comprises an alcohol compartment connection hole that nears the second side relative to the first side , the first path connects the alcohol compartment connection hole to the first sample compartment connection hole for transferring the alcohol from the alcohol compartment to the sample compartment , and at least one portion of the first path is located between the alcohol compartment and the second side . <EOS>