Students, trade unionists and parents with children marched through Tokyo's Shibuya district to music and chants, carrying flags written with "Close all nuke plants at once!" and "No More Fukushima."
The demonstration, called before Kan’s statement, was the latest reaction to the 11 March explosion at the Fukushima Daiichi plant.
Media said on Saturday that Japan's anti-nuclear movement could become more vocal after Kan's call for a Hamaoka shutdown.
The prime minister said he made the decision "out of concerns for public safety," citing a forecast by government experts that put at 87 per cent the chance of a magnitude 8.0 quake hitting the area served by Chubu Electric within the next 30 years.
Chubu Electric held a board meeting on Saturday to discuss Kan's decision, but did not reach a decision on whether to comply with his request, which is not legally binding.
"The decision is still under discussion," a spokesperson said. "We therefore cannot say when exactly the decision will be made, but we would like to reach one quickly."
Japan and the US are to scrap a deadline of 2014 for relocating a US military base on the Japanese island of Okinawa, the Yomiuri Shimbun daily reported Saturday.
The two governments concluded it would be extremely difficult to meet the
deadline, set by Prime Minister Naoto Kan after he was elected, the paper quoted an unnamed Japanese government source as saying.
Local people have long complained of aircraft noise, the risk of accidents and lawlessness of some personnel at the US Marine Corps Air Station Futenma.