Abstract: Provided are a client and a server which filter errors in signal data collected in a wireless signal map creating process and increase accuracy of a signal map, and a wireless signal map creating system using the same. The wireless signal map creating system collects a local wireless signal map, stores a global wireless signal map, calculates a predicted signal strength of a specific point using a reception strength of at least one point located adjacent to the specific point in the local wireless signal map, compares a wireless signal strength of the specific point in the local wireless signal map and a predicted signal strength to determine an error or not, and updates the global wireless signal map based on a determination result.