Provided is a lens connector-testing device including a base, a circuit tester, a probe, and a positioning unit. The positioning unit includes a positioning housing, a lift block, an insulating plate, a press spring, a latch member and a supporting seat. The positioning housing has a lift-guiding groove. The insulating plate is fixedly connected to an upper end of the lift block. A lower end of the lift block is slidably received in the lift-guiding groove. A holding space is defined between the insulating plate and the positioning housing. The supporting seat is disposed on the positioning housing and has at least one electrical contact. The latch member has a fixing section, a hooking section, and a pressing section. The lift block has a projecting portion matched with the hooking section of the latch member. The press spring is located between the pressing section and the positioning housing.