An object recognition apparatus comprising: detecting means mounted on a mobile body and for acquiring a detection signal representing an object (64, 66) that exists within a detectable area; and feature quantity estimating means for estimating a plurality of feature quantities with respect to a relative position or motion of the object (64, 66) with respect to the mobile body, using the detection signal acquired by the detecting means and a set of estimation coefficients, wherein the detectable area has a sectional shape whose central point is located at a position of the mobile body and whose central angle (2θd) falls within a predetermined range, and the detectable area is formed of particular end areas (80, 88, 92) existing respectively at both ends of a near part of the sectional shape and an ordinary area (82, 84, 86, 90, 94) which is a remaining area of the sectional shape, wherein the plurality of feature quantities include a widthwise feature quantity representing a behavior of the object (64, 66) along a widthwise direction; and wherein the feature quantity estimating means estimates the plurality of feature quantities using the set of estimation coefficients whose inheritance possibility to inherit an estimated result of the widthwise feature quantity is higher at the particular end areas (80, 88, 92) than at the ordinary area (82, 84, 94) in at least one of the widthwise direction of the mobile body and an angular direction (θ), depending on a position of the object (64, 66) approaching the particular end areas (80, 88, 92), and wherein the feature quantity estimating means sequentially estimates the plurality of feature quantities with a Kalman filter according to a state space model that describes a time series of a state vector whose vector components are represented by the plurality of feature quantities. detecting means mounted on a mobile body and for acquiring a detection signal representing an object (64, 66) that exists within a detectable area; and feature quantity estimating means for estimating a plurality of feature quantities with respect to a relative position or motion of the object (64, 66) with respect to the mobile body, using the detection signal acquired by the detecting means and a set of estimation coefficients, wherein the detectable area has a sectional shape whose central point is located at a position of the mobile body and whose central angle (2θd) falls within a predetermined range, and the detectable area is formed of particular end areas (80, 88, 92) existing respectively at both ends of a near part of the sectional shape and an ordinary area (82, 84, 86, 90, 94) which is a remaining area of the sectional shape, wherein the plurality of feature quantities include a widthwise feature quantity representing a behavior of the object (64, 66) along a widthwise direction; and wherein the feature quantity estimating means estimates the plurality of feature quantities using the set of estimation coefficients whose inheritance possibility to inherit an estimated result of the widthwise feature quantity is higher at the particular end areas (80, 88, 92) than at the ordinary area (82, 84, 94) in at least one of the widthwise direction of the mobile body and an angular direction (θ), depending on a position of the object (64, 66) approaching the particular end areas (80, 88, 92), and wherein the feature quantity estimating means sequentially estimates the plurality of feature quantities with a Kalman filter according to a state space model that describes a time series of a state vector whose vector components are represented by the plurality of feature quantities.