To provide a capacitance variable circuit and communication system for easy controlling of characteristics by applying a voltage.

Fixed capacitance capacitors Cd1-Cd5, and variable capacitance capacitors Ct1-Ct5 using a thin film dielectric layer whose specific inductive capacity changes according to an applied voltage, are connected in series. A plurality of paired capacitors A-E are connected in which a voltage is applied between the fixed capacitance capacitors Cd1-Cd5 and variable capacitance capacitors Ct1-Ct5. The changes in specific inductive capacity of the variable capacitance capacitors Ct1-Ct5 of the plurality of paired capacitors A-E are almost identical, and the plurality of paired capacitors A-E are commonly supplied with a voltage in a variable capacitance circuit. Since a voltage can be commonly applied to the variable capacitance capacitors Ct1-Ct5 of the paired capacitors A-E, voltage control is easy.