A self-position estimation device includes: a target position detection unit mounted in a vehicle, the target position detection unit being configured to detect a relative position of a target present around the vehicle and the vehicle; a movement amount estimation unit configured to estimate a movement amount of the vehicle; a target position accumulation unit configured to move the detected relative position by the estimated movement amount and to accumulate the moved relative position as target position data; a map information acquisition unit configured to acquire map information including target position information of a target present on a map; a curve start position estimation unit configured to estimate a curve start position of a travel path on which the vehicle travels; and a self-position estimation unit configured to perform comparison in which at least the target position data present around the vehicle and the target position data present between a current position of the vehicle and the estimated curve start position, of the accumulated target position data, is compared with the target position information included in the map information to estimate a self position which is the current position of the vehicle.