A voltage smoothing circuit includes a first multilayer capacitor, a second multilayer capacitor, and a regulator including an input terminal electrically connected to the second multilayer capacitor and an output terminal electrically connected to the first multilayer capacitor. The regulator calculates a first voltage applied to the first multilayer capacitor based on a second voltage applied to the second multilayer capacitor from the input terminal such that a potential difference which is applied to the first multilayer capacitor decreases or increases when a potential difference which is applied to the second multilayer capacitor increases or decreases, and outputs the first voltage from the output terminal.
