Disclosed is technology relating to a device and method for detecting bypass access and account theft. In the method for detecting bypass access from a client to a server according to the present invention: a server receives access data comprising data about hops on the route from the client to the server by using a route tracing agent; region data is extracted from the IP address(es) of the hop(s) comprised in the received access data; a judgment is made as to whether the extracted region data belongs to a pre-set access-permitted region; and the server detects whether the access from the client is bypass access, in accordance with the judgment results.