noun
Refers to a person who draws up a plan, proposal, or draft. Often used in business, policy, or project contexts.
彼は新事業の立案者として知られている。
He is known as the planner of the new business venture.
起草者 is specifically the drafter of a document, law, or statement, whereas 立案者 can be used more broadly for any plan or scheme.
Compound of 立案 (りつあん, 'planning' or 'drafting') and 者 (しゃ, 'person').