PURPOSE: To test a liquid through simple operation by providing a containing member which is at least partly transparent and can accommodate a solid testing agent and an inflow hole of a liquid to be tested at an end of said containing member which is the size not to pass said testing agent.

CONSTITUTION: A containing member 1 is formed of plastic in a generally cylindrical shape. An upper end of the member 1 is cut with right angles to the elongated direction thereof and a lower end thereof is cut with an inclination of about 45° to the elongated direction. An upper sealing part 2 and a lower sealing part 3 are formed respectively at the upper and lower ends of the cylindrical member 1, whereby the interior of the member 1 is tightly sealed. A spherical testing agent 4 having the diameter about half the member 1 is placed inside the member 1. The testing agent 4 is hooked halfway by the sealing part 3 when the testing agent 4 stands up. Thereafter, an inflow hole 6 is formed in the size not to pass the testing agent 4 by cutting the lower part of the sealing part 3. While the air inside the member 1 is partly discharged by pressing the center of the member 1, the hole 6 is dipped in a liquid 8 to be tested. Then, the member 1 is released from being pressed. Accordingly, the member 1 is returned to the original state by the elasticity, whereby the liquid 8 is sucked inside the member 1 through the hole 6. The testing agent 4 is soaked in the liquid 8. Thus, the liquid 8 can be tested through reaction between the agent 4 and the liquid.