VACUUM EJECTOR AND SEAL VALVE UNIT

In a vacuum ejector provided with a seal valve mechanism between a vacuum generation mechanism and a break flow path, the seal valve mechanism includes a valve plug that is biased toward a sealing opening from the break flow path side to block the seal opening, and is configured to open the seal opening by moving the valve plug away from the seal opening using a piston portion that operates according to supply air supplied from the vacuum generation mechanism.