This study tries to answer some ever-existent questions in writing fields regarding approaching the most effective ways to give feedback to students' errors in writing by comparing the effect of error correction and error detection on the improvement of students' writing ability. In order to achieve this goal, 60 pre-intermediate English learners were randomly divided into two groups: the first one was Direct Feedback Group, receiving feedback on their writing through error correction (DFG) and the other one was Indirect Feedback Group (IFG), receiving feedback in their writing through error detection along with the codes. The learners were taking English classes in a private English center and were supposed to self-correct and hand in their writings when received indirect error feedback. The results suggested that error detection along with the codes led to better improvement in the learners' writing than the error correction treatment.