To provide a light beam type safety device with the invalidation control function capable of displaying an invalid area of a light curtain with a simple additional constitution.

This light beam type safety device has light emitting control circuits 121to 12nand 131to 13nrepeatedly emitting the light in order from light receiving display elements LED1to LEDnin response to a light receiving output signal and a repetitive signal of respective channels generated synchronously with time sharing signals P1to Pnfor emitting the optical axis in order, a false signal generating circuit generating a false light receiving signal for falsely generating a light receiving output signal synchronously with its time sharing signals P1to Pnon an invalid channel invalidly set by an invalidity control manual switch, and an invalidity indicating flashing signal generating circuit 30 generating an invalid channel indicating flashing signal for flashing and emitting the light from the light receiving display elements LED1to LEDnof the invalid channel in a visually confirmable period longer than a period of the repetitive signal in response to the false light receiving signal.

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