diff --git a/src/transformers/models/longformer/tokenization_longformer.py b/src/transformers/models/longformer/tokenization_longformer.py
index bca7b9bc8f0..d841b4147c1 100644
--- a/src/transformers/models/longformer/tokenization_longformer.py
+++ b/src/transformers/models/longformer/tokenization_longformer.py
@@ -20,7 +20,7 @@ from ..roberta.tokenization_roberta import RobertaTokenizer
 logger = logging.get_logger(__name__)
 
 
-VOCAB_FILES_NAMES = {"vocab_file": "vocab.json", "merge_file": "merges.txt"}
+VOCAB_FILES_NAMES = {"vocab_file": "vocab.json", "merges_file": "merges.txt"}
 
 PRETRAINED_VOCAB_FILES_MAP = {
     "vocab_file": {
@@ -30,7 +30,7 @@ PRETRAINED_VOCAB_FILES_MAP = {
         "allenai/longformer-base-4096-extra.pos.embd.only": "https://huggingface.co/allenai/longformer-base-4096-extra.pos.embd.only/resolve/main/vocab.json",
         "allenai/longformer-large-4096-extra.pos.embd.only": "https://huggingface.co/allenai/longformer-large-4096-extra.pos.embd.only/resolve/main/vocab.json",
     },
-    "merge_file": {
+    "merges_file": {
         "allenai/longformer-base-4096": "https://huggingface.co/allenai/longformer-base-4096/resolve/main/merges.txt",
         "allenai/longformer-large-4096": "https://huggingface.co/allenai/longformer-large-4096/resolve/main/merges.txt",
         "allenai/longformer-large-4096-finetuned-triviaqa": "https://huggingface.co/allenai/longformer-large-4096-finetuned-triviaqa/resolve/main/merges.txt",
diff --git a/src/transformers/models/longformer/tokenization_longformer_fast.py b/src/transformers/models/longformer/tokenization_longformer_fast.py
index a25d17db7d0..a42346fcd7e 100644
--- a/src/transformers/models/longformer/tokenization_longformer_fast.py
+++ b/src/transformers/models/longformer/tokenization_longformer_fast.py
@@ -21,7 +21,7 @@ from .tokenization_longformer import LongformerTokenizer
 logger = logging.get_logger(__name__)
 
 
-VOCAB_FILES_NAMES = {"vocab_file": "vocab.json", "merge_file": "merges.txt", "tokenizer_file": "tokenizer.json"}
+VOCAB_FILES_NAMES = {"vocab_file": "vocab.json", "merges_file": "merges.txt", "tokenizer_file": "tokenizer.json"}
 
 PRETRAINED_VOCAB_FILES_MAP = {
     "vocab_file": {
@@ -31,7 +31,7 @@ PRETRAINED_VOCAB_FILES_MAP = {
         "allenai/longformer-base-4096-extra.pos.embd.only": "https://huggingface.co/allenai/longformer-base-4096-extra.pos.embd.only/resolve/main/vocab.json",
         "allenai/longformer-large-4096-extra.pos.embd.only": "https://huggingface.co/allenai/longformer-large-4096-extra.pos.embd.only/resolve/main/vocab.json",
     },
-    "merge_file": {
+    "merges_file": {
         "allenai/longformer-base-4096": "https://huggingface.co/allenai/longformer-base-4096/resolve/main/merges.txt",
         "allenai/longformer-large-4096": "https://huggingface.co/allenai/longformer-large-4096/resolve/main/merges.txt",
         "allenai/longformer-large-4096-finetuned-triviaqa": "https://huggingface.co/allenai/longformer-large-4096-finetuned-triviaqa/resolve/main/merges.txt",