The Pankhurst Centre has been broken into twice within 24 hours- once by a man looking for a place to sleep.
The historic building on Nelson Street was targeted by intruders on Sunday evening, and again in the early hours of Monday morning.
The windows of the parlour where Emmeline Pankurst founded the suffragette movement in 1903 were smashed during the break in.
Mid-century suffragette sashes and a door were also damaged.
A man was found sleeping on one of the children's sleeping bags inside the centre after the alarm went off.
Gail Heath, CEO of the Pankhurst Trust, said the damage and increasing security will cost the charity thousands of pounds.
The trust has set up a JustGiving page to help pay for the repairs on the Grade 2 listed building.
Gail Heath said: "We are heartbroken that the Pankhurst Centre, which symbolises so much in the campaign for women’s equality should suffer this set back.
"It’s also a tragedy, and extremely sad, that it was someone seeking shelter for the night that led to this incident.
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“We are already a museum fighting for our future, our current survival depends upon the support of volunteers and donations, with no public funding in place.
"This major set back comes as we near the eve of the anniversary of the founding of the suffragette movement, which we plan to mark with events, family fun, tea parties in the parlour, talks and much more beginning from 8 October.
"We will continue with the planned programme of activities, galvanised by the persistence of spirit of the suffragettes, as this is the only way we know how."
The terraced property opposite Manchester Royal Infirmary became the birthplace of the votes for women movement in 1903 when the Women's Social and Political Union was formed there.
It was the home of Emmeline Pankhurst and her daughters Sylvia, Adela and Christabel.
Now it is the home of the small Pankhurst Centre museum and Manchester Women’s Aid, a charity supporting women and children affected by domestic violence.
The centre receives no public funding for maintenance and management, instead being forced to rely on voluntary work, donations and small grants.
The Manchester Evening News has contacted Greater Manchester Police for a comment.
