A Montgomery County judge who presided over a murder trial growing out of a discount store shooting in which a county police officer and a security guard were killed, refused yesterday to disqualify himself from presiding at the trial of a second defendant.

Curtis Wayne Monroe faces trial on charges of murdering security guard David Wayne Myers and attempting to murder store manager Douglas Cummins Jr., who was wounded in the incident at a W. Bell store at White Oak on March 27, 1981. Monroe's attorney, Barry Helfand, argued that Judge William M. Cave should pass the case on to another judge because he presided over the trial last November of James Arthur Calhoun, who was convicted of murdering the security guard and a police officer and has been sentenced to death.

At Calhoun's trial, Cave permitted testimony from Cummins, a prosecution witness who had been hypnotized by a Montgomery County police lieutenant in an effort to have him recall details of the shootings.

Helfand said that at Monroe's trial he will call two experts on hypnotism who believe that testimony from a person who has been hypnotized is not reliable because there are opportunities for the person administering the hypnosis to influence the witness.

"What concerns us," Helfand told Judge Cave, "is that in effect you have made a determination that the hypnotist did everything properly.

"My ruling might be different if the testimony is different," the judge responded. Cave refused to remove himself from the case, expected to run for three weeks, because he is the only Circuit Court judge available to hear it this summer.