In a container including two accommodation parts each accommodating liquid, mixing of the liquids in a case of moving magnetic particles in the liquid accommodated in one accommodation part to the other accommodation part is suppressed. Provided is a container includes a first accommodation part which accommodates a first liquid containing magnetic particles, a second accommodation part which accommodates separated magnetic particles separated from the first liquid, and a second liquid, and a flow passage which allows the first accommodation part and the second accommodation part to communicate with each other, and through which the separated magnetic particles pass, in which the flow passage has a first staircase part including two or more steps from an inner bottom surface of the first accommodation part on a first accommodation part side.