A connection arrangement for connecting a vertical element, such as a column or a wall element, and a beam to each other, the connection arrangement comprising: - a beam part fastenable to an end of the beam, which beam part comprises an end plate in which there is a downwardly open slot, at the bottom of which there is an abutment surface, and - a column part fastenable to the vertical element, which column part comprises a tongue part having a support surface against which the abutment surface of the slot is arranged to be supported in order to receive a vertical load, - on opposite sides of the tongue part there are upper support surfaces, and in an upper part of the slot, on opposite sides, there are upper abutment surfaces, one of which is arranged to be supported against one of the upper support surfaces of the tongue part when the beam part has been installed onto the column part and a torsional moment tending to cause rotation about the longitudinal axis of the beam acts on the beam part, - on opposite sides of the tongue part there are lower support surfaces, and a housing is fastened to a back surface of the end plate on either side of the slot, inside which housing the lower support surfaces of the tongue part are arranged when the beam part has been installed onto the column part, - an inner side surface of the housing is arranged to be supported to the lower support surface of the tongue part when a torsional moment tending to cause rotation about the longitudinal axis of the beam acts on the beam part, characterized in that - on the side of the tongue part there is an inclined side support surface, which is inside the housing when the beam part has been installed onto the column part, - the connection arrangement comprises a wedge which is arrangeable against the inclined side support surface and the inner surface of the housing in order to support the tongue part to the inner side surface of the housing, and - the tongue part comprises a body plate and an end support plate which is fastened from its front surface to an end of the body plate and which extends higher than the support surface, the side surfaces of which end support plate form the lower support surfaces, a wedging plate, a front surface of which is fastened to a back surface of the end support plate and on opposite sides of which there are said inclined side support surfaces, and a protective plate, a front surface of which is fastened to a back surface of the wedging plate and which is wider than the wedging plate, and which end support plate, wedging plate and protective plate are inside the housing. - a beam part fastenable to an end of the beam, which beam part comprises an end plate in which there is a downwardly open slot, at the bottom of which there is an abutment surface, and - a column part fastenable to the vertical element, which column part comprises a tongue part having a support surface against which the abutment surface of the slot is arranged to be supported in order to receive a vertical load, - on opposite sides of the tongue part there are upper support surfaces, and in an upper part of the slot, on opposite sides, there are upper abutment surfaces, one of which is arranged to be supported against one of the upper support surfaces of the tongue part when the beam part has been installed onto the column part and a torsional moment tending to cause rotation about the longitudinal axis of the beam acts on the beam part, - on opposite sides of the tongue part there are lower support surfaces, and a housing is fastened to a back surface of the end plate on either side of the slot, inside which housing the lower support surfaces of the tongue part are arranged when the beam part has been installed onto the column part, - an inner side surface of the housing is arranged to be supported to the lower support surface of the tongue part when a torsional moment tending to cause rotation about the longitudinal axis of the beam acts on the beam part, characterized in that - on the side of the tongue part there is an inclined side support surface, which is inside the housing when the beam part has been installed onto the column part, - the connection arrangement comprises a wedge which is arrangeable against the inclined side support surface and the inner surface of the housing in order to support the tongue part to the inner side surface of the housing, and - the tongue part comprises a body plate and an end support plate which is fastened from its front surface to an end of the body plate and which extends higher than the support surface, the side surfaces of which end support plate form the lower support surfaces, a wedging plate, a front surface of which is fastened to a back surface of the end support plate and on opposite sides of which there are said inclined side support surfaces, and a protective plate, a front surface of which is fastened to a back surface of the wedging plate and which is wider than the wedging plate, and which end support plate, wedging plate and protective plate are inside the housing.