To provide a heating transpiration insecticidal liquid which is effective in controlling sanitary insects such as mosquitos in an insecticidal liquid used in a heating transpiration insecticidal method where an absorbed insecticidal liquid is transpired by absorbing the insecticidal liquid with a liquid-absorbing wick partially immersed in the insecticidal liquid and by heating the part of the wick not being immersed in the insecticidal liquid.

This heating transpiration insecticidal liquid is an insecticidal liquid used in a heating transpiration insecticidal method where an absorbed insecticidal liquid is transpired by absorbing the insecticidal liquid with a liquid- absorbing wick partially immersed in the insecticidal liquid and by heating the part of the wick not being immersed in the insecticidal liquid and comprises 2,3,5,6-tetrafluoro-4-methylbenzyl 3-(2-chloro-2-fluorovinyl)-2,2- dimethylcyclopropanecarboxylate as an effective ingredient.