A waste container with a lower gate opening mechanism operable by means of interaction with a holding and operating device attached to a container lifting arm, said container including: a waste storage receptacle provided with waste inlets in its upper half and with a discharge opening on its lower face; one or more gates articulated with respect to the receptacle to allow their movement between a closed position in which said one or more gates completely block the discharge opening, and an open position in which they free up the discharge opening which allows emptying the receptacle by gravity; a handle attached to the upper half of the receptacle to allow holding and lifting thereof through said holding and operating device; an operating head accessible from outside the receptacle and located in the upper half thereof, said operating head including an axially movable rod, envisaged for allowing the interaction thereof with the mentioned holding and operating device; a multiplier mechanism integrated in said receptacle connecting the operating head with the one or more gates by means of a kinematic chain, converting movement of the operating head into a larger movement of the gates; wherein said multiplier mechanism integrates a knee mechanism formed by a first bar with a first end articulated with respect to the receptacle and a second end articulated with respect to a first end of a second bar, which in turn has a second end articulated with respect to a movable part of the multiplier mechanism, a point of the knee mechanism, located between the first end of the first bar and the second end of the second bar, characterized in that said knee mechanism is kinematically connected to the rod of the operating head by means of at least one articulated third bar, said kinematic connection determining a movement of said point of the knee mechanism due to the operation of the operating head, modifying the angle formed by the intersection between the first bar and the second bar, between a gate closing position, in which the smaller angle formed by said intersection is between 180° and 140°, and a gate opening position in which the intersection of said first and second bars forms a second angle greater than the first angle. a waste storage receptacle provided with waste inlets in its upper half and with a discharge opening on its lower face; one or more gates articulated with respect to the receptacle to allow their movement between a closed position in which said one or more gates completely block the discharge opening, and an open position in which they free up the discharge opening which allows emptying the receptacle by gravity; a handle attached to the upper half of the receptacle to allow holding and lifting thereof through said holding and operating device; an operating head accessible from outside the receptacle and located in the upper half thereof, said operating head including an axially movable rod, envisaged for allowing the interaction thereof with the mentioned holding and operating device; a multiplier mechanism integrated in said receptacle connecting the operating head with the one or more gates by means of a kinematic chain, converting movement of the operating head into a larger movement of the gates; wherein said multiplier mechanism integrates a knee mechanism formed by a first bar with a first end articulated with respect to the receptacle and a second end articulated with respect to a first end of a second bar, which in turn has a second end articulated with respect to a movable part of the multiplier mechanism, a point of the knee mechanism, located between the first end of the first bar and the second end of the second bar, characterized in that said knee mechanism is kinematically connected to the rod of the operating head by means of at least one articulated third bar, said kinematic connection determining a movement of said point of the knee mechanism due to the operation of the operating head, modifying the angle formed by the intersection between the first bar and the second bar, between a gate closing position, in which the smaller angle formed by said intersection is between 180° and 140°, and a gate opening position in which the intersection of said first and second bars forms a second angle greater than the first angle.