A collision determination device (1, 1A) comprising: vehicle route candidate acquisition means for acquiring a route candidate of a host vehicle; other object status acquisition means for acquiring the status of the other object (H, M2); shortest arrival time calculation means for calculating a shortest arrival time, at which the other object (H, M2) can arrive at each point of the route candidate of the host vehicle acquired by the vehicle route candidate acquisition means when moving with a predetermined first displacement, on the basis of the status of the other object (H, M2) acquired by the other object status acquisition means; characterised by: longest stopover time calculation means for calculating a longest stopover time, at which the other object (H, M2) passes through each point of the route candidate of the host vehicle acquired by the vehicle route candidate acquisition means when reducing speed with a predetermined second displacement, on the basis of the status of the other object (H, M2) acquired by the other object status acquisition means, wherein the longest stopover time at which the other object (H, M2) passes through each point represents a latest time at which the other object (H, M2) passes by each point; and collision determination means for determining the possibility of collision between the host vehicle and the other object (H, M2) on the basis of the shortest arrival time calculated by the shortest arrival time calculation means, the longest stopover time calculated by the longest stopover time calculation means, and the passage time at each point of the host vehicle, wherein, when the shortest arrival time calculated by the shortest arrival time calculation means is smaller than the passage time at each point of the route candidate of the host vehicle, and the longest stopover time calculated by the longest stopover time calculation means is greater than the passage time at each point of the route candidate of the host vehicle, the collision determination means determines that there is a possibility that the host vehicle collides with the other object (H, M2). vehicle route candidate acquisition means for acquiring a route candidate of a host vehicle; other object status acquisition means for acquiring the status of the other object (H, M2); shortest arrival time calculation means for calculating a shortest arrival time, at which the other object (H, M2) can arrive at each point of the route candidate of the host vehicle acquired by the vehicle route candidate acquisition means when moving with a predetermined first displacement, on the basis of the status of the other object (H, M2) acquired by the other object status acquisition means; characterised by: longest stopover time calculation means for calculating a longest stopover time, at which the other object (H, M2) passes through each point of the route candidate of the host vehicle acquired by the vehicle route candidate acquisition means when reducing speed with a predetermined second displacement, on the basis of the status of the other object (H, M2) acquired by the other object status acquisition means, wherein the longest stopover time at which the other object (H, M2) passes through each point represents a latest time at which the other object (H, M2) passes by each point; and collision determination means for determining the possibility of collision between the host vehicle and the other object (H, M2) on the basis of the shortest arrival time calculated by the shortest arrival time calculation means, the longest stopover time calculated by the longest stopover time calculation means, and the passage time at each point of the host vehicle, wherein, when the shortest arrival time calculated by the shortest arrival time calculation means is smaller than the passage time at each point of the route candidate of the host vehicle, and the longest stopover time calculated by the longest stopover time calculation means is greater than the passage time at each point of the route candidate of the host vehicle, the collision determination means determines that there is a possibility that the host vehicle collides with the other object (H, M2). longest stopover time calculation means for calculating a longest stopover time, at which the other object (H, M2) passes through each point of the route candidate of the host vehicle acquired by the vehicle route candidate acquisition means when reducing speed with a predetermined second displacement, on the basis of the status of the other object (H, M2) acquired by the other object status acquisition means, wherein the longest stopover time at which the other object (H, M2) passes through each point represents a latest time at which the other object (H, M2) passes by each point; and collision determination means for determining the possibility of collision between the host vehicle and the other object (H, M2) on the basis of the shortest arrival time calculated by the shortest arrival time calculation means, the longest stopover time calculated by the longest stopover time calculation means, and the passage time at each point of the host vehicle, wherein, when the shortest arrival time calculated by the shortest arrival time calculation means is smaller than the passage time at each point of the route candidate of the host vehicle, and the longest stopover time calculated by the longest stopover time calculation means is greater than the passage time at each point of the route candidate of the host vehicle, the collision determination means determines that there is a possibility that the host vehicle collides with the other object (H, M2).