A power module including a main housing, a power element, and at least one assembling component is provided. The main housing has at least one side wall and at least two ribs extending from the side wall. The power element is disposed in the main housing and is closely pressed against a heat dissipation structure by the side wall. The assembling component includes a main section and two bending sections. The main section is located between the two ribs and includes a central portion, at least one movable component, and a peripheral portion. The central portion has a fastening portion, the peripheral portion surrounds the central portion, and the movable component is connected between the central portion and the peripheral portion. The two bending sections are respectively connected to two opposite sides of the peripheral portion and are respectively embedded in the two ribs.