Many routing protocols in mobile ad-hoc networks have been developed by many researchers. One of ad-hoc routing protocol types is the on-demand routing that establishes a route to a destination node only when required. But it is necessary to re-establish a new route when its route breaks down. However, most of on-demand routing protocols re-establish a new route after a route break.In this paper, we propose a new route maintenance algorithm to avoid route breaks because each intermediate node on an active route detects a danger of a link break to an upstream node and re-establishes a new route before a route break. We propose this algorithm based on AODV (Ad-hoc On-demand Distance Vector routing protocol) that is one of the routing protocols under study by the IETF MANET Working Group. Then, we evaluate the performance of our proposal by computer simulations.