A membrane filtration system and a membrane bio reactor including the same are described. In an example, the membrane filtration system includes: a treatment tank; a membrane support frame disposed in the treatment tank and mounted with a filtration membrane; a reciprocating portion connected to the membrane support frame and reciprocating the membrane support frame; a sliding portion disposed in the treatment tank, connected to the reciprocating portion, and guiding a moving direction of the membrane support frame; and a sludge lifting portion flexibly disposed at a lower end of the membrane support frame to lift sludge accumulated at a lower part of the treatment tank.