The present invention relates to a liquid (31, 32, 33) and gel-like medium (21) is loaded magnetic particles operation device (10). The device (10) includes a first liquid storage portion in which the first liquid (31) is accommodated and (3a), second liquid storage portion in which the second liquid (32) is housed and (3b), the comprises third liquid reservoir in which the liquid (33) is accommodated in the 3 (3c), the first gel medium accommodating portion in which the first gel medium (21) is housed and (2a). The first liquid storage portion (3a), is connected to the second liquid storage portion (3b) and the third liquid storage portion (3c) is first gelled medium containing part (2a), a first gel-like medium by (21), the first liquid (31), the second liquid (32) and the third liquid (33) are separated.