An acceleration sensor includes a CV conversion circuit, an AD conversion circuit, and first and second registers. The CV conversion circuit outputs a voltage corresponding to the capacitance changes between a movable electrode and each of first and second fixed electrodes disposed to face the movable electrode. The AD conversion circuit is connected to the CV conversion circuit and has a first detection range and a second detection range. The first register is connected to the AD conversion circuit and holds a first value. The second register is connected to the AD conversion circuit and holds a second value. The first value contains information about an acceleration in the first detection range, and the second value contains information about an acceleration in the second detection range. The first and second values indicate accelerations in the same direction.