The present invention does not require an electrical circuit, compact operating costs to provide a water heater with a dissolver and it supplies inexpensive inorganic compounds. The apparatus includes a water circuit 15, powdered or granular, or a storage means 12 for storing an inorganic compound 11 is a mixture of powder and granule, and a filtering means 13, the water circuit 15 the flowing water, the stored in the storage means 12 to dissolve the inorganic compound 11, the dissolved inorganic compounds 11, a dissolving device which is characterized in that it has a structure that passes through the filtering means 13, water and inorganic material is moved in a dissolved concentration difference between the compounds, the principle of material diffusion (Ficks law), I dissolving an inorganic compound in water. [Selection Figure] Figure 1【課題】電気回路を必要とせず、コンパクトで運転コストが安価な無機化合物等を供給する溶解装置及びそれを備えた給湯装置を提供すること。【解決手段】水回路15と、粉末状または顆粒状、あるいは、粉末状と顆粒状との混合物である無機化合物11を収納する収納手段12と、濾過手段13とを備え、前記水回路15を流れる水に、前記収納手段12に収納された無機化合物11を溶解させ、前記溶解された無機化合物11が、前記濾過手段13を通過する構成としたことを特徴とする溶解装置で、水と無機化合物の間の溶解濃度差で物質が移動する、物質拡散(フィックの法則)の原理で、水に無機化合物を溶解させる。【選択図】図1
