To provide a dissolving device capable of preventing such a trouble that a piping in the dissolving device is clogged by undissolved powder medicine for dialysis by preventing excessive supply of the powder medicine for dialysis.SOLUTION: A dissolving device 1 includes: a dissolving part 61； a water supply part 62 for supplying water to the dissolving part 61； a medicine supply part 63 for supplying powder medicine for dialysis to the dissolving part 61； an electric conductivity meter 30 for detecting the electric conductivity of a solution in which medicine is dissolved in water in the dissolving part 61； and a control part 50 for controlling the medicine supply part 63 on the basis of the electric conductivity of the solution, detected with the electric conductivity meter 30. The control part 50 stops supply of the medicine from the medicine supply part 63 when it is detected that a direction of a change in the electric conductivity is changed from an increase direction to a decrease direction, or the electric conductivity does not increase before the electric conductivity of the solution, detected with the electric conductivity meter 30 reaches a target value in dissolving operation of dissolving the medicine in water in the dissolving part 61.SELECTED DRAWING: Figure 1【課題】透析用粉末薬剤を過剰に供給することを防止して、未溶解の透析用粉末薬剤で溶解装置内の配管が詰まるなどの不具合を防止することのできる溶解装置を提供する。【解決手段】溶解部６１と、溶解部６１に水を供給する給水部６２と、溶解部６１に透析用粉末薬剤を供給する薬剤供給部６３と、溶解部６１で水に薬剤が溶解された溶液の電気伝導率を検出する電気伝導率計３０と、電気伝導率計３０により検出される溶液の電気伝導率に基づいて薬剤供給部６３の制御を行う制御部５０と、を有する溶解装置１は、制御部５０が、溶解部６１で水に薬剤を溶解する溶解動作において、電気伝導率計３０により検出される溶液の電気伝導率が目標値に達する前に、該電気伝導率の変化の方向が増加方向から減少方向に変化したこと又は該電気伝導率が増加しなくなったことを検知した場合に、薬剤供給部６３からの薬剤の供給を停止する構成とする。【選択図】図１
