The role and effect of coacervation-inducing agents such as butyl rubber, polyethylene and polyisobutylene in microencapsulation were investigated by using phase separation from cyclohexane solution with change of temperature. Ascorbic acid was used as a core material and ethylcellulose was used as a wall-forming material. Among the three different coacervation-inducing agents, polyisobutylene was suitable for microencapsulation, resulting in low aggregation of microcapsules and a slow dissolution rate. The role of coacervation-inducing agents in microencapsulation was investigated with polyisobutylene. Polyisobutylene changed the gel into a coacervate and resulted in the formation of smooth and thick-walled microcapsules. It also largely prevented the aggregation of microcapsules.