To improve heat radiation performance in an electronic controller having a circuit board on which an electronic component is mounted including a heat-generating element, and the electronic component is covered with a filling agent to be protected from external influences, resulting in improving reliability of the electronic controller.

An EDU (enjector driving unit) 10 is provided with a heat-generating element 15 causing heat generation, a circuit board 14 whose one surface is mounted with the heat-generating element 15, a heat radiation plate 17 to be attached on the other surface of the circuit board 14, and a case for housing the circuit board 14. A gel-like filling agent 18 is filled inside the case 11 so that the heat-generating element 15 is submerged. In this configuration, a protrusion-like heat absorber 13a is provided in the case 11, and the heat absorber 13a is provided so as to closely oppose the heat-generating element 15 in the gel-like filling agent 18.