There is provided a capacitor unit including plural capacitors, each including end face electrode at one end face and side face electrode having a polarity different from end face electrode at a side face, arranged side by side; bus bar connected to end face electrode of capacitor, and partially connected to side face electrode of adjacent capacitor unit; and a circuit substrate arranged at the one end face sides or the other end face sides of plural capacitors; wherein bus bar and the circuit substrate are electrically connected through conductive portion arranged from bus bar towards the circuit substrate.