In order to deal with the recent rapid increase in Internet traffic, it is necessary to use network bandwidth over the entire optical fiber more efficiently. Therefore, elastic optical path networks that enable efficient spectrum utilization on optical fibers by allocating bandwidth to optical paths using granular optical spectra are expected. Elastic optical path networks require the routing, modulation level, and spectrum allocation (RMLSA) to efficiently allocate optical spectrum resources to optical paths. In this paper, we propose novel RMLSA algorithms that reduce occupied spectrum resources on the entire network by considering multiple candidate routes as well as the shortest route that is allocated to optical paths. The evaluation results of our proposed algorithms can reduce occupied spectrum resources and allocate network resources efficiently.