WASHINGTON (AP) _ Deputy Secretary of State John C. Whitehead will travel to four Soviet bloc countries next week to continue a Reagan administration effort to improve relations with Eastern Europe, the State Department announced today.

Whitehead, the No. 2 officer in the State Department, will meet leaders in Czechoslovakia, Poland, Romania and Bulgaria on an 11-day trip beginning Jan. 30, department spokesman Charles E. Redman said.

It will be Whitehead's fourth visit to the region.

''Mr. Whitehead will stess the importance we attach to the protection of human rights and the commitments these governments have undertaken'' under international agreements, Redman said. He said Whitehead also would meet with religious leaders and ''a broad cross section of society.''

Enroute to Eastern Europe he will go to Paris for a meeting of the committee established by the industrialized democracies to control the flow of military-usable technology to the Soviet Union and its allies.

On the way home, Whitehead will stop in Brussels to brief NATO representative s on the outcome of the trip, Redman said.

Whitehead, who visited East Germany, Hungary and Yugoslavia last fall, has been active in U.S. policy toward Soviet bloc countries and has been the highest-level U.S. visitor to Czechoslovakia and East Germany in many years.

In preparation, he invited the ambassadors from Hungary, Bulgaria and Czechoslovakia to meet him at the State Department today. He scheduled a session with the Polish envoy later this week.

In recent years - roughly parallel with an effort by Soviet leader Mikhail Gorbachev to gain influence in Western Europe - the Reagan administration has increased its diplomatic overtures to the Soviets' allies in East Europe.

Whitehead and other officials have given the Eastern Europeans regular briefings on U.S. views of arms control, human rights and U.S.-Soviet relations.

On the economic front, the administration has sought to increase trade with Eastern European countries, notably Hungary, Poland and Romania, which have been granted most-favored-nation trade benefits.