Abstract: A device for demoulding pieces in a mould comprises a skid comprising a slider for housing a figure insert for moulding of a negative of the piece to be moulded, said slider being associated with a pushrod that can move said slider to an ejection position of a piece to be moulded pushing at least one ejection plate, and it is characterized in that said pushrod is placed substantially perpendicular with respect to said at least one ejection plate. Due to this substantially vertical arrangement of the pushrod the construction of the mould is simplified, minimizing the width needed for placing the device inside the mould.