To provide a charger which enables a user to connect cables, without taking the polarity of battery terminals into consideration.

The charger 1 is provided with a relay circuit 10 which becomes any of the first continuity state where the plus charge terminal 7 of a charge circuit 9 and the first cable 4 make a continuity and besides a minus charge terminal 8 and the second cable 5 make a continuity, the second continuity state where the plus charge terminal 7 and the second cable 5 make a continuity and besides the minus charge terminal 8 and the first cable 4 make a continuity, and the non-continuity state where the charge terminals 7 and 8 and the cables 4 and 5 make no continuity. It is further provided with a judgement control circuit 11 which puts the relay circuit 10 in the first continuity state or the second continuity state, judging the polarity of the battery terminals 3a and 3b attached to each cable 4 and 5, based on the battery voltage generated between both cables 4 and 5, when both cables 4 and 5 are attached to battery terminals 3a and 3b.