A switch wire-connection terminal block structure includes a casing and at least one contact terminal. The contact terminal has a locking hole in direct communication with a receiving hole. The receiving hole communicates with a wire socket. A locking member is disposed in the receiving hole and lockable in the locking hole. A gasket member is fitted on the locking member. A guide channel is formed on inner wall of the receiving hole and extends in a locking direction of the locking member. The gasket member has a guide section extending in a direction reverse to the locking direction of the locking member. The guide section is slidably disposed in the guide channel. The receiving hole provides a larger locking travel for the locking member so that the terminal block is applicable to closed wire terminal.