To provide a MOSFET antiphase control dimmer capable of increasing the load rating of equipment through limiting of a rush current.

An antiphase control dimmer, having a built-in MOSFET part 1 with two MOSFETs connected in series with an AC power supply E along the opposite directions and a built-in drive power supply part 2 for driving the MOSFET part 1, and subjecting the AC power supply E to antiphase control by means of the MOSFET part 1 to control power supplied to load, is provided with a timer circuit 7 transmitting outputs to a control part 6 for a certain period during actuation, a source voltage comparison circuit part 5 for monitoring the AC power supply E, and a control part 6 operated by signals from the source voltage comparison circuit part 5 and the timer circuit 7. The timer circuit 7 operates for a certain period from the time of actuation, and during the period in which the AC power supply E exceeds a certain voltage, the MOSFETs are turned off by the source voltage comparison circuit 5 and the control part 6 irrespective of the on command width of the control signal, whereby the upper limit of a rush current is limited.