Fetching details from the dictionary...

same feeling; same sentiment; same opinion; sympathy; agreement; concurrence
彼の意見に私も同感だと思いました。
I also thought I agreed with his opinion.
同感です、私もそう思っています。
I agree, I was thinking the same thing.
多くの人が彼女の発言に同感を示した。
Many people showed agreement with her statement.