The Administrative Procedure Act (APA) has been passed in 1999. However, the administrative law academics in Taiwan seemed to pay little attention upon the "rulemaking procedure" in APA. Perhaps the reason why is that the rulemaking procedure provisions in APA are learned front the United States, a country where most of our administrative law scholars have not been familiar. The author introduces the American experiences of rulemaking procedures, shows that such procedures can correct the bias and defects of Traditional-Administrative-Law-Model. The Model merely focuses upon the concrete administrative decisions, insisting that the goal of administrative law is to protect people from government abuse. The real policy-making administrative action - rulemaking - is usually ignored. Such a Model imposes insufficient control upon administrative authority, however, and they cannot ensure the accountability and democratic character of agency decisionmaking. The rulemaking procedures in APA, specially the "notice-and-comment" procedure can revise such incapability of traditional Model, because it can expand the public participation, strengthen the democratic and judicial control of administration. Some scholars consider that the rulemaking procedure provisions are declaratory in nature. This Article opposes such a proposition. The, author argues that the rulemaking procedures - notice-and-comment, publication of internal yules.… - are legally binding, i.e. if the agency promulgates. legislative rule without observing the notice-and-comment procedure, or even paying insufficient considerations upon the relevant pro-and-con opinion, the rule is void and the Grand Justices or reviewing courts have the duty to invalidate it and remand the agency to reopen procedures. If the internal rule, has never been published in the government register or bulletin, the agency cannot cite them to make decisions, and any person may not in any manner be required to reort to, or be adversely affected by them.