A switch failure detection device includes switches provided on branch paths, current detection units provided on the branch paths, the current detection units being configured to output a current detection signal, a storage unit configured to store an initial value of the current detection signal, the initial value being output from the current detection units, a switch control unit to turn off one of the plurality of switches one by one with at least another one of the plurality of switches being turned on and a first failure detection unit configured to compare the initial value and a value of a first current detection signal output from a corresponding one of the current detection units when the one of the switches is turned off, the first failure detection unit being further configured to detect a first failure of the plurality of switches based on a result of the comparison.