The present invention relates to a shoulder strap positioner for releasably connecting a first and a second strap of a child restraining seat harness, where the shoulder strap positioner comprises a male member configured to be connected to a first strap of the child restraining seat harness and a female member configured to be connected to a second strap of the child restraining seat harness, and where the male member can be removably connected to the female member (1b), where the female member comprises a receptacle provided with an opening for insertion of the male member, the opening being provided over a part of a circumference of the female member, where at least one rib is provided over a part of the opening, and where the male member comprises an tongue provided with a groove, the male and female members being locked to each other through a movement of the male member towards the at least one rib, the at least one rib being brought into contact and accommodated in the groove through this movement, and released from each other through a movement of the male member away from the at least one rib.