An automobile door checker includes a case secured to a door, a check plate that runs movably through the case and has its base end pivotably supported on a body, a detent member fitted into and retained by the case and working in cooperation with a detent face of the check plate and a resilient member that is formed from a resilient material and is provided in a compressed state in a housing chamber defined between an outer end face of the detent member and an inner end face of the case, wherein the resilient member substantially and tightly fills the housing chamber, thus preventing rainwater from infiltrating into the housing chamber. In this way, it is possible to prevent infiltration of rainwater into a housing chamber of a case housing a resilient member by a simple structure.