FLUID HEATING DEVICE

To achieve downsizing of a fluid heating device.SOLUTION: A fluid heating device 100 includes: a switching element 41 (an electric component) which controls energization of a heater 18; a heat transfer body 20 which transmits heat of the heater 18 to a fluid; and a tank 10 forming a fluid chamber 8, through which the fluid circulates, with the heat transfer body 20. The heat transfer body 20 has: a heating part 21 incorporating the heater 18; a partition wall part 25 which closes an opening 15 of the tank 10 and partitions an electric chamber 9 from the fluid chamber; and a cavity part 39 which forms a heat radiation passage 3a, which transmits heat of the switching element 41 to the fluid, between the heating part 21 and the partition wall part 25.SELECTED DRAWING: Figure 1 【課題】流体加熱装置の小型化を図ること。【解決手段】流体加熱装置１００は、ヒータ１８の通電を制御するスイッチング素子４１（電装部品）と、ヒータ１８の熱を流体に伝える伝熱体２０と、伝熱体２０との間に流体が流通する流体室８を形成するタンク１０と、を備える。伝熱体２０は、ヒータ１８を内蔵する加熱部２１と、タンク１０の開口部１５を閉塞する電装室９とを仕切る隔壁部２５と、加熱部２１と隔壁部２５との間にスイッチング素子４１の熱を流体に伝える放熱流路３ａを形成する空洞部３９と、を有する。【選択図】図１