On September  13, 1950, sis separate informations  for robbery  were filed in the Court of  First Instance of Rizal against  Salvador Poblador, Armando  Gustillo and Rene Escares.  When these  cases  were  called  for  hearing  on March 2, 1951, Rene Escares  was still at large and,  by agreement  of the parties,  they were tried jointly against Salvador Poblador and Armando Gustillo.  A decision was thereafter  rendered against them finding them guilty of the crimes charged and convicting them accordingly.

On April  21,  1954, Rene Escares  was  arraigned  and pleaded not guilty in each of the six above-mentioned cases but later he asked permission to withdraw his former plea of not guilty and substitute it for a plea of guilty.  The trial court granted the petition and forthwith it rendered a decision  of the following tenor:

''When  these cases were called for  trial,  the  accused asked permission to withdraw his former plea of not guilty and substitute it with that of guilty in all these cases. The Court granted  said petition, and the accused forthwith freely and voluntarily pleaded guilty in all these cases.

"Wherefore,  the Court finds the accused  Rene Escares  guilty of the crimes charged  in the information in all these  cases, and, in accordance with the provisions of Article 70 of the  Revised Penal Code,  hereby sentences said accused to twelve  (12) years, six (6) months, and ono (1) day in all the cases, with all the accessories of the law, and to pay the costs."

Rene  Escares  appealed  from  the decision but  having taken the case to the  Court of Appeals, the latter certified it to  us  on the ground that the only issue involved is  one of law.

The only question  raised  in this appeal refers to the penalty imposed  on the appellant.   He contends that since he pleaded guilty to all the crimes charged and there is no aggravating circumstance  to  offset it, the  penalty to be imposed on him  should be reduced  to the minimum.

It should be noted that the imposable penalty in each of the six cases where appellant  pleaded guilty in accordance with  paragraph 5, Article 294, of the Revised Penal Code, is prision  correctional in its  maximum period to prision mayor in its  medium period, which should be applied in its minimum period in view of the mitigating circumstance of plea of guilty, not offset by any aggravating  circumstance, or from 4 years 2 months and 1 day to 6 years one month and 10 days.  Applying the Indeterminate Sentence Law, the appellant should be  sentenced  for  each crime to an indeterminate penalty the minimum of which shall not be less than 4 months and 1 day of arresto mayor nor more than 4 years and 2 months of prision, correctional,  and the maximum shall not be less than 4 years 2 months and 1 day of prision correctional nor more than 6 years 1 month and 10 days  of prision mayor.  But in applying the  proper penalty, the trial court imposed upon appellant the three fold  rule provided for  in paragraph 4 of Article 70 of the Revised Penal Code.  This is an error for said article can only be taken into account, not in the  imposition of the penalty, but in connection with  the service of the sentence imposed.

The penalty  imposed  upon appellant by the trial court should therefore be modified  in  the sense that he should suffer in each of the six cases an indeterminate penalty of not less than 4 months  and 1 day  of arresto mayor and not more than  4  years 2 months and  1 day of  prision correctional, plus  the  corresponding accessory penalties provided for by law.  These penalties should be served in accordance with the limitation prescribed in paragraph 4, Article 70, of the Revised Penal Code.

Modified  in  the sense above  indicated, we affirm the decision of the trial court, with costs  against  appellant.

Paras, C. J.,  Bengzon, Padilla, Montemayor, Reyes, A., Labrador, Concepcion,  Reyes, J. B. L., Endencia and Felix, JJ., concur.