The present disclosure provides a cleaning string for cleaning a tip end face of a single core optical connector, which contains a quite small residual amount of oil components and has a high wiping property without the attachment of oil components to the tip end face of a single core optical connector.Further, the present disclosure provides a method for producing a cleaning string for cleaning a connector which can suitably remove oil components adhering to a multifilament made of chemical fibers.A cleaning string for cleaning a connector formed by twisting plural multifilament made of chemical fibers, wherein a residual amount of oil components is 3 mg/g or less.A method for producing a cleaning string for cleaning a connector which comprises a step of removing oil components adhering to multifilament made of chemical fibers by washing with a surfactant-containing solution in a form of knitting, reel, or honeycomb wound before or after twisting plural multifilament made of chemical fibers, a step of washing with pure water, a step of drying and a step of unwinding the form.