A position controlling device for a carpenter angle drill/hollow chisel mortiser has a mounting group, a positioning group, and a retaining arm. The mounting group has two crossbars and a bridge bar. The bridge bar is connected to the crossbars. The positioning group is connected to the mounting group, and has two limiting blocks, a holding frame, and a circuit breaker. The limiting blocks are connected to the bridge bar between the crossbars. The holding frame is securely connected to one of the limiting blocks. The circuit breaker is mounted in the holding frame and has a contacting slice and an electric wire. The contacting slice is elastically connected to the circuit breaker, and transversally extends out of the holding frame. The retaining arm selectively abuts the contacting slice of the circuit breaker to enable the circuit breaker at a turn-off condition.