Vehicular door latch device

A vehicular door latch device comprising:

• a latch having an engagement groove that is inwardly recessed from an outer circumference of the latch, a full latch interlock section and a half latch interlock section that are both formed on the outer circumference of the latch, wherein the latch rotates in accordance with opening and closing of a door;
• a striker provided in a vehicle body that engages with the engagement groove;
• a ratchet that is disposed to be in contact with the latch, wherein the ratchet interlocks with the full latch interlock section and holds the latch in a first posture when the door is in a fully-closed state, and the ratchet interlocks with the half latch interlock section and holds the latch in a second posture when the door is in a half-closed state;
• and
• an operation unit, said operation unit comprising a locking and unlocking mechanism whose posture is switched between an unlocked posture in which interlock between the latch and the ratchet can be canceled and a locked posture in which the interlock cannot be canceled, through posture change of the locking and unlocking mechanism caused by an operation of the operation unit;
• and
• a detection lever being in contact with the outer circumference of the latch and being configured to retract from a movement trajectory of the locking and unlocking mechanism so as to permit the locking and unlocking mechanism to be switched from the unlocked posture to the locked posture when the latch is in the first posture, and to enter the movement trajectory of the locking and unlocking mechanism so as to prohibit the posture change of the locking and unlocking mechanism by blocking the locking and unlocking mechanism when the latch is in the second posture,
• wherein the locking and unlocking mechanism comprises a movable lever being configured to, when the locking and unlocking mechanism is in the locked posture while the latch is not in the first posture, come into contact with the detection lever that enters the movement trajectory of the locking and unlocking mechanism, and to rotate such that the locking and unlocking mechanism is switched to the unlocked posture.