动画制作人。动画制作公司MADHOUSE、MAPPA、Studio M2创立者，现任MAPPA代表取缔役会长、StudioM2代表取缔役社长。宮城县盐灶市出身、法政大学毕业。

　　从日本动画业界的黎明时期就作为制作人活跃至今的元老之一。也因在制作现场亲手做饭款待员工而广为人知。

　　大学毕业后，有过成为自由职业者的经历，于1965年经熟人的介绍入职虫制作公司（旧）。当时因为手冢治虫所率领的虫制作处于制作电视动画的初创期，所以也身陷在人手无论如何也不足、连睡眠时间也没有的状况下进行制作。关于在身边一起工作的手冢治虫，他回忆道：“他是一个工作那么久我也没碰见的，在常识范围内无法想象出来的人物”，并说：“被他的魅力迷住，无法从动画世界中逃脱”。

　　1972年，虫制作公司的经营危机之际，与出崎统、林太郎、川尻善昭等人一起独立并成立有限公司Mad・House（现为株式会社MADHOUSE）。1980年，因为出崎统与杉野昭夫退出MADHOUSE另外成立スタジオあんなぷる，就任MADHOUSE的总经理（至2000年为止）。

　　之后，除了参与许多的OVA与电视系列动画，在影院作品中也担当今敏导演的《蓝色恐惧》、《千年女优》、《东京教父》、《红辣椒》的企划与制片，还在2006年发掘了细田守的才能，对细田提出《穿越时空的少女》的电影企划并实现了电影化。

　　2002年，荣获第7回神户动画奖特别奖。2003年，荣获第23回藤本赏奖励奖。

　　2011年6月从MADHOUSE退职之后，在MADHOUSE的旧址阿佐谷成立MAPPA。在渡边信一郎的导演之作《坂道上的阿波罗》中担当企划，作为该社成立的第一部作品。

　　2016年4月，将社长让与作为MAPPA成立成员、晚辈大冢学，自己就任董事长。同时成立“StudioM2”，就任该社社长。同年秋天，推出从成立之初就参与的片渊须直导演之作《在这世界的角落》。

Masao Maruyama (丸山 正雄, born June 19, 1941) is a Japanese anime producer and anime entrepreneur, the co-founder of Madhouse, as well as the founder of MAPPA and Studio M2. He is the current chairman of MAPPA and president of Studio M2.

Maruyama has been involved in the Japanese animation business for over 50 years. He has worked with many well-known and up-and-coming animators, established several animation production companies, worked on dozens of series and films, and planned and produced various works.

Maruyama is one of the most experienced producers in the Japanese animation industry and has given opportunities to individuals who went on to become accomplished directors in their own right. Among the talents he picked up were Satoshi Kon, Mamoru Hosoda, and Sunao Katabuchi. He also gave Masaaki Yuasa and Mitsuo Iso a chance to direct at a very early stage. He also gave Mamoru Hosoda, who was thinking of returning to his hometown to change careers after he was forced to drop out of directing Studio Ghibli's Howl's Moving Castle, a chance to direct his first theatrical film after resigning from Toei Animation. Yuichiro Hayashi, Munehisa Sakai, and Sunghoo Park, who became MAPPA's main directors, and Sayo Yamamoto, his direct protégé at Madhouse, are also people whose talents were discovered by Maruyama. His ability to find talented people helped Madhouse and MAPPA to make great strides.