A boom of a personnel hoist that comprises: a first boom part, provided with a joint allowing lifting and lowering of the first boom part; a second boom part; a connecting member with which the boom parts (3a, 3b) are permanently connected to each other; at least one joint with which the second boom part is connected to the connecting member, whereby the second boom part is lifted and lowered in relation to said joint; at least one man cage that is arranged to the top part of the second boom part; wherein the boom has a transport position in which the boom parts (3a, 3b) are substantially horizontally side by side and their axes are on different vertical planes; characterized in that the connecting member comprises a first connection part and a second connection part, and the first connection part is fastened to the top end of the first boom part and the second connection part is fastened to the bottom end of the second boom part; between the connection parts (10a, 10b), there is at least one turning axis that is parallel to that of the first boom part; the connecting member comprises at least one turning device (17a, 17b) for moving the second connection part in relation to the first connection part around the turning axis; and the boom has a turning position in which the second connection part and the second boom part fastened thereto are turned in a position in which the axes of the boom parts (3a, 3b) are substantially on the same vertical plane; the connecting member comprises one or more pressure medium operated cylinders serving as the at least one turning device (17a, 17b), whereby the linear motion of the one or more pressure medium operated cylinders is transformed into a turning motion. a first boom part, provided with a joint allowing lifting and lowering of the first boom part; a second boom part; a connecting member with which the boom parts (3a, 3b) are permanently connected to each other; at least one joint with which the second boom part is connected to the connecting member, whereby the second boom part is lifted and lowered in relation to said joint; at least one man cage that is arranged to the top part of the second boom part; wherein the boom has a transport position in which the boom parts (3a, 3b) are substantially horizontally side by side and their axes are on different vertical planes; characterized in that the connecting member comprises a first connection part and a second connection part, and the first connection part is fastened to the top end of the first boom part and the second connection part is fastened to the bottom end of the second boom part; between the connection parts (10a, 10b), there is at least one turning axis that is parallel to that of the first boom part; the connecting member comprises at least one turning device (17a, 17b) for moving the second connection part in relation to the first connection part around the turning axis; and the boom has a turning position in which the second connection part and the second boom part fastened thereto are turned in a position in which the axes of the boom parts (3a, 3b) are substantially on the same vertical plane; the connecting member comprises one or more pressure medium operated cylinders serving as the at least one turning device (17a, 17b), whereby the linear motion of the one or more pressure medium operated cylinders is transformed into a turning motion.