A liquid level detecting device (40, 80, 100, 130, 150, 170, 200, 230, 250, 270) comprising: a pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) that are disposed so as to oppose one another, wherein the liquid level detecting device (40, 80, 100, 130, 150, 170, 200, 230, 250, 270) is adapted to detect an electrostatic capacitance between the opposing portions of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) which changes depending on a liquid level to be detected; and a variable structure that is adapted to vary a surface area of an overlapping region of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) or a distance between the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254), and that, by changing the surface area or the distance by a predetermined amount, is adapted to switch between a first detection electrode arrangement (70A, 74A, 124A, 214A, 264A) of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) and a second detection electrode arrangement (70B, 74B, 124B, 214B, 264B) of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) that have different electrode patterns for detecting the electrostatic capacitance; characterized in that the variable structure has a driving structure (60, 132, 232, 272) that is adapted to slide at least one of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) relatively with respect to the other or to rotate at least one of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) relatively with respect to the other around a rotational axis disposed at one end portion in the longitudinal direction of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254), thereby switching between the first detection electrode arrangement (70A, 74A, 124A, 214A, 264A) and the second detection electrode arrangement (70B, 74B, 124B, 214B, 264B); and the liquid level detecting device (40, 80, 100, 130, 150, 170, 200, 230, 250, 270) is adapted to detect the liquid level on the basis of at least an electrostatic capacitance detected at the first detection electrode arrangement (70A, 74A, 124A, 214A, 264A) and an electrostatic capacitance detected at the second detection electrode arrangement (70B, 74B, 124B, 214B, 264B). a pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) that are disposed so as to oppose one another, wherein the liquid level detecting device (40, 80, 100, 130, 150, 170, 200, 230, 250, 270) is adapted to detect an electrostatic capacitance between the opposing portions of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) which changes depending on a liquid level to be detected; and a variable structure that is adapted to vary a surface area of an overlapping region of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) or a distance between the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254), and that, by changing the surface area or the distance by a predetermined amount, is adapted to switch between a first detection electrode arrangement (70A, 74A, 124A, 214A, 264A) of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) and a second detection electrode arrangement (70B, 74B, 124B, 214B, 264B) of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) that have different electrode patterns for detecting the electrostatic capacitance; characterized in that the variable structure has a driving structure (60, 132, 232, 272) that is adapted to slide at least one of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) relatively with respect to the other or to rotate at least one of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254) relatively with respect to the other around a rotational axis disposed at one end portion in the longitudinal direction of the pair of electrode plates (42, 44, 102, 104, 152, 154, 172, 174, 204, 208, 252, 254), thereby switching between the first detection electrode arrangement (70A, 74A, 124A, 214A, 264A) and the second detection electrode arrangement (70B, 74B, 124B, 214B, 264B); and the liquid level detecting device (40, 80, 100, 130, 150, 170, 200, 230, 250, 270) is adapted to detect the liquid level on the basis of at least an electrostatic capacitance detected at the first detection electrode arrangement (70A, 74A, 124A, 214A, 264A) and an electrostatic capacitance detected at the second detection electrode arrangement (70B, 74B, 124B, 214B, 264B).