This opening/closing body control device for vehicles comprises a lock device and a control device. The control device comprises: a reversal control unit; a reversal stopping unit; a first error detection unit that detects a first state change error in a first neutral switch, when reverse rotation of a rotating member has been stopped on the basis of a change in the on/off state of a second neutral switch during reverse control after closing control; and a second error detection unit that detects a second state change error in the first neutral switch, when reverse rotation of the rotating member is stopped on the basis of a change in the on/off state of the second neutral switch during reverse control after release control.