The former Finance minister expressed the need to take the agitation launched by Hardik Patel for the cause of farmers across the country.
Sinha visited the quota spearhead at his residence near Ahmedabad.
He was accompanied by BJP MP Shatrughan Sinha, former BJP chief minister of Gujarat Suresh Mehta and ex-BJP MP from Maharashtra Nana Patole.
Hardik Patel had launched indefinite fast on August 25 for demands including a farm loan waiver and reservation for the Patidar community under OBC category in jobs and education.
The state BJP government has dubbed Hardik Patel's hunger strike "politically motivated".
"The issues on which Hardik Patel is holding fast have created an impact across the country. The issues are being discussed everywhere," he told reporters after meeting Hardik Patel.
Sinha, the convener of political action group Rashtra Manch, said the agitation launched by Hardik Patel should be taken to various parts of the country.
"One thing that we decided after a short discussion with Hardik Patel is that we need to take this agitation across the country and fight strongly," Sinha said.
He said the issues plaguing farmers in the country are serious and that farmers be granted a permanent relief including a loan waiver.
"We stand with Hardik Patel who has been raising the issue of farmers. Now the time has come that we fight together. We discussed this with him and we hope that the government wakes up now and initiate steps to resolve Hardik Patel's demands," the former BJP leader said.
Responding to a query on caste quota, Sinha said the Union government should chart out a way forward as people from various communities who are outside the scope of reservation have demanded it.
"The Central government should think about this. It has formed a backward class commission. It should think on how to take this matter forward. As far as possible, we should try to work to improve (lives) of many communities who have lagged behind, as per Constitution," he said.
Shatrughan Sinha said their meeting with Hardik Patel was not politically motivated.
"We gathered here in a non-political capacity on the basis of humanity. We are here because our aim is to construct the temple of humanity. We have no objection on mandir-masjid (sic)," he said.
Hardik Patel had launched his hunger strike on the third anniversary of his mega pro-quota rally in Ahmedabad.
He had Sunday released his "will" in which he divided his property among his parents, a sister, 14 youths killed during the quota agitation in 2015 and a panjrapole (shelter for ill and old cows) near his village.
Apart from the Congress, leaders and representatives of the Aam Aadmi Party, Trinamool Congress, Nationalist Congress Party, Rashtriya Janata Dal and Hindustani Awami Morcha (HAM) have so far visited Hardik Patel at his residence and extended their support.