Emotion cause extraction is a challenging task nowadays. Causes behind emotions are extracted from textual data. Emotion cause extraction has many applications such as extracting causes from reviews that are extracted from social networks and recommender websites where users give their feedback. The resources in this field are limited. There are some corpora built for western languages like English and far east languages like Chinese. Arabic language resources in this field are very limited. This paper introduces emotion cause detection in Arabic Language. A dialectal Arabic annotated corpus is built for the purpose of emotion cause extraction. The data collected from many resources. Sequence labelling techniques are applied with IOB2 scheme using BiLSTM-CRF algorithm and BERT-CRF algorithm. BERT-CRF outperforms BiLSTM-CRF in both span-level and token-level measure evaluation. BERT-CRF achieves a 0.29 F1 score in case of span-level measure evaluation and a 0.84 F1 score in case of token-level measure evaluation.