A disconnection detection apparatus for determining disconnection, comprising: an amplification unit configured to differentially amplify a first sinusoidal wave and a second sinusoidal wave which are applied thereto, wherein the second sinusoidal wave has a phase difference of 90 degrees with respect to the first sinusoidal wave; a first conversion unit configured to convert an amplified first sinusoidal wave signal and an amplified second sinusoidal wave into absolute values, respectively; and a first determination unit configured to determine, if the amplification unit receives the first sinusoidal wave, that disconnection occurs when an absolute value of the first sinusoidal wave is less than a first comparison value and at the same time an absolute value of the second sinusoidal wave is less than a second comparison value, wherein the second comparison value is greater than the first comparison value, wherein the first determination unit is configured to determine, if the amplification unit receives the second sinusoidal wave, that the disconnection occurs when the absolute value of the second sinusoidal wave is less than the first comparison value and at the same time the absolute value of the first sinusoidal wave is less than the second comparison value, wherein the first determination unit is further configured to determine the first sinusoidal wave as not being disconnected when the absolute value of the first sinusoidal wave is greater than the first comparison value, wherein the first determination unit is still further configured to determine, when the absolute value of the second sinusoidal wave is greater than the first comparison value, the second sinusoidal wave as not being disconnected, wherein the disconnection detection apparatus further comprises: a second conversion unit configured to convert the amplified first sinusoidal wave signal and the amplified second sinusoidal wave signal into a first square wave signal and a second square wave signal, respectively; and a second determination unit configured to determine that disconnection occurs when the second square wave signal does not vary while the first square wave signal varies. an amplification unit configured to differentially amplify a first sinusoidal wave and a second sinusoidal wave which are applied thereto, wherein the second sinusoidal wave has a phase difference of 90 degrees with respect to the first sinusoidal wave; a first conversion unit configured to convert an amplified first sinusoidal wave signal and an amplified second sinusoidal wave into absolute values, respectively; and a first determination unit configured to determine, if the amplification unit receives the first sinusoidal wave, that disconnection occurs when an absolute value of the first sinusoidal wave is less than a first comparison value and at the same time an absolute value of the second sinusoidal wave is less than a second comparison value, wherein the second comparison value is greater than the first comparison value, wherein the first determination unit is configured to determine, if the amplification unit receives the second sinusoidal wave, that the disconnection occurs when the absolute value of the second sinusoidal wave is less than the first comparison value and at the same time the absolute value of the first sinusoidal wave is less than the second comparison value, wherein the first determination unit is further configured to determine the first sinusoidal wave as not being disconnected when the absolute value of the first sinusoidal wave is greater than the first comparison value, wherein the first determination unit is still further configured to determine, when the absolute value of the second sinusoidal wave is greater than the first comparison value, the second sinusoidal wave as not being disconnected, wherein the disconnection detection apparatus further comprises: a second conversion unit configured to convert the amplified first sinusoidal wave signal and the amplified second sinusoidal wave signal into a first square wave signal and a second square wave signal, respectively; and a second determination unit configured to determine that disconnection occurs when the second square wave signal does not vary while the first square wave signal varies. a second conversion unit configured to convert the amplified first sinusoidal wave signal and the amplified second sinusoidal wave signal into a first square wave signal and a second square wave signal, respectively; and a second determination unit configured to determine that disconnection occurs when the second square wave signal does not vary while the first square wave signal varies.