A latch device includes a base member that has an entering groove having a deep side wall, a latch including an engaging groove having a restraining wall, and a ratchet that meshes with the latch in a meshed position. The latch device further includes a cam member that rotates the latch to a restrained position. In the restrained position, the cam member abuts against the latch to nip a striker between the deep side wall and the restraining wall. The restraining wall includes an inclined surface approaching the deep side wall toward an inlet side of the engaging groove at least in the meshed position.