A solution such as a washing liquid can be passed through a separation column such as a nozzle tip having a solid phase quickly and reliably, thereby achieving improvements in throughput. A sample processing device comprises a separation column having a carrier capable of capturing a target substance, a liquid supply passage capable of supplying a liquid from one end portion of the separation column to the other end portion thereof, and a communication passage disposed independently of the liquid supply passage and capable of providing communication between the inside of the separation column and the outside. The communication between the inside of the separation column and the outside by the communication passage is controlled.